
// Make newform 126.2.m.a in Magma, downloaded from the LMFDB on 25 April 2024.
// To make the character of type GrpDrchElt, type "MakeCharacter_126_m();"
// To make the character of type GrpDrchElt with Codomain the HeckeField, type "MakeCharacter_126_m_Hecke();"
// To make the coeffs of the qexp of the newform in the Hecke field type "qexpCoeffs();"
// To make the newform (type ModFrm), type "MakeNewformModFrm_126_2_m_a();".
// This may take a long time!  To see verbose output, uncomment the SetVerbose lines below.
// The precision argument determines an initial guess on how many Fourier coefficients to use.
// This guess is increased enough to uniquely determine the newform.
// To make the Hecke irreducible modular symbols subspace (type ModSym)
// containing the newform, type "MakeNewformModSym_126_2_m_a();".
// This may take a long time!  To see verbose output, uncomment the SetVerbose line below.
// The default sign is -1.  You can change this with the optional parameter "sign".
function ConvertToHeckeField(input: pass_field := false, Kf := [])
    if not pass_field then
        poly := [6561, 0, -4374, 0, 729, 0, 486, 0, -288, 0, 54, 0, 9, 0, -6, 0, 1];
        Kf := NumberField(Polynomial([elt : elt in poly]));
        AssignNames(~Kf, ["nu"]);
    end if;
    Rf_num := [[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [2187, 0, -1458, 0, 135, 0, 126, 0, -81, 0, 9, 0, 3, 0, -1, 0], [-8748, -10935, -729, 3402, 5346, -486, -594, -396, -162, 54, 216, 36, -36, -15, -3, -2], [6561, 10935, 7290, -3402, -3240, 486, 1242, 396, -162, -54, -162, -36, 27, 15, -6, 2], [-3645, 0, 972, 0, 648, 0, -576, 0, 108, 0, 18, 0, -21, 0, 2, 0], [0, 13122, 0, -9477, 0, 2754, 0, 468, 0, -432, 0, 144, 0, 12, 0, -5], [67797, 21870, -18954, -9720, 162, -486, 2160, 1638, -486, -540, 108, 18, 9, 24, 6, -4], [0, -4374, 0, 729, 0, 486, 0, -288, 0, 54, 0, 9, 0, -6, 0, 1], [0, -9477, 0, 972, 0, 648, 0, -576, 0, 108, 0, 18, 0, -21, 0, 2], [5832, 0, -3483, 0, 198, 0, 432, 0, -180, 0, 12, 0, 10, 0, -3, 0], [0, 0, 0, -324, 0, -108, 0, 45, 0, -27, 0, 0, 0, 3, 0, -1], [0, -2187, 0, 1458, 0, -135, 0, -126, 0, 81, 0, -9, 0, -3, 0, 1], [0, 8748, 0, -4617, 0, 54, 0, 792, 0, -216, 0, 0, 0, 18, 0, -5], [0, 3645, 0, -4050, 0, 0, 0, 684, 0, -324, 0, 18, 0, 21, 0, -8], [83106, -8748, -37179, 6075, -6804, -1782, 7398, 198, -2268, 54, -54, -72, 198, 12, -51, 1]];
    Rf_basisdens := [1, 1, 1458, 17496, 17496, 5832, 17496, 17496, 2187, 5832, 1944, 1458, 1458, 5832, 5832, 17496];
    Rf_basisnums := ChangeUniverse([[z : z in elt] : elt in Rf_num], Kf);
    Rfbasis := [Rf_basisnums[i]/Rf_basisdens[i] : i in [1..Degree(Kf)]];
    inp_vec := Vector(Rfbasis)*ChangeRing(Transpose(Matrix([[elt : elt in row] : row in input])),Kf);
    return Eltseq(inp_vec);
end function;


// To make the character of type GrpDrchElt, type "MakeCharacter_126_m();"
function MakeCharacter_126_m()
    N := 126;
    order := 6;
    char_gens := [29, 73];
    v := [5, 3];
    // chi(gens[i]) = zeta^v[i]
    assert UnitGenerators(DirichletGroup(N)) eq char_gens;
    F := CyclotomicField(order);
    chi := DirichletCharacterFromValuesOnUnitGenerators(DirichletGroup(N,F),[F|F.1^e:e in v]);
    return MinimalBaseRingCharacter(chi);
end function;

// To make the character of type GrpDrchElt with Codomain the HeckeField, type "MakeCharacter_126_m_Hecke();"
function MakeCharacter_126_m_Hecke(Kf)
    N := 126;
    order := 6;
    char_gens := [29, 73];
    char_values := [[0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [-1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]];
    assert UnitGenerators(DirichletGroup(N)) eq char_gens;
    values := ConvertToHeckeField(char_values : pass_field := true, Kf := Kf); // the value of chi on the gens as elements in the Hecke field
    F := Universe(values);// the Hecke field
    chi := DirichletCharacterFromValuesOnUnitGenerators(DirichletGroup(N,F),values);
    return chi;
end function;


function ExtendMultiplicatively(weight, aps, character)
    prec := NextPrime(NthPrime(#aps)) - 1; // we will able to figure out a_0 ... a_prec
    primes := PrimesUpTo(prec);
    prime_powers := primes;
    assert #primes eq #aps;
    log_prec := Floor(Log(prec)/Log(2)); // prec < 2^(log_prec+1)
    F := Universe(aps);
    FXY<X, Y> := PolynomialRing(F, 2);
    // 1/(1 - a_p T + p^(weight - 1) * char(p) T^2) = 1 + a_p T + a_{p^2} T^2 + ...
    R<T> := PowerSeriesRing(FXY : Precision := log_prec + 1);
    recursion := Coefficients(1/(1 - X*T + Y*T^2));
    coeffs := [F!0: i in [1..(prec+1)]];
    coeffs[1] := 1; //a_1
    for i := 1 to #primes do
        p := primes[i];
        coeffs[p] := aps[i];
        b := p^(weight - 1) * F!character(p);
        r := 2;
        p_power := p * p;
        //deals with powers of p
        while p_power le prec do
            Append(~prime_powers, p_power);
            coeffs[p_power] := Evaluate(recursion[r + 1], [aps[i], b]);
            p_power *:= p;
            r +:= 1;
        end while;    
    end for;
    Sort(~prime_powers);
    for pp in prime_powers do
        for k := 1 to Floor(prec/pp) do
            if GCD(k, pp) eq 1 then
                coeffs[pp*k] := coeffs[pp]*coeffs[k];
            end if;
        end for;
    end for;
    return coeffs;
end function;


function qexpCoeffs()
    // To make the coeffs of the qexp of the newform in the Hecke field type "qexpCoeffs();"
    weight := 2;
    raw_aps := [[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0], [0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 0, -1, 0, 1, 0, 0, -1, 0, -1, 1, 0], [0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0], [-1, -1, 0, -1, 1, -1, 0, 0, -1, 0, 1, -1, 1, -2, 2, -2], [0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 0, -1, -1, 1, 0, 0], [0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, -1, -1, 0], [0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, -1, 0], [-4, 1, -1, 2, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, -1, 1], [0, 0, 0, 0, -2, 0, -1, 0, 1, -1, -2, 0, -1, 1, -1, 0], [0, 1, 0, 0, 0, 0, 1, 0, -2, -1, 0, 1, 2, -1, 1, 0], [-2, 1, -2, 0, 4, -2, 2, 2, -1, 2, 4, 1, 3, -2, 2, 0], [0, -1, 0, 0, 0, 0, 1, 0, -1, 0, 0, 1, -3, 1, 2, 0], [1, -1, 2, -1, -1, 1, 0, -2, -1, 0, -1, -1, -1, 0, 0, 0], [0, -4, 0, 0, 0, 0, -3, 0, -1, -1, 0, 0, -1, 1, -1, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, -1, 0, 0, 0, 0, 1, 0, 2, -3, 0, 0, 2, 0, -2, 0], [0, -3, 0, 0, 0, 0, 1, 0, 2, -2, 0, -2, 0, -2, 0, 0], [0, 0, 5, 0, -1, -4, -1, 1, 1, -1, 5, 0, 0, 0, 0, -1], [-1, 0, -2, -1, 0, 3, 1, -1, -1, 1, 0, 0, 0, 0, 0, 1], [0, 0, 0, 0, 0, 0, -1, 0, 0, 1, 0, 2, -2, -1, 1, 0], [1, -1, 8, 3, -1, 1, -2, -2, 1, -2, -4, -1, -3, 2, -2, 0], [0, 1, 0, 0, 0, 0, 3, 0, -2, -2, 0, -3, 7, -4, 7, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 0], [0, 1, 0, 0, 0, 0, 0, 0, -1, 1, 0, -5, 1, -6, -1, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -5, 4, -5, 0], [0, 4, 0, 0, 0, 0, 4, 0, 2, 6, 0, 0, 2, 0, 2, 0], [5, 1, -1, -1, 0, -11, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1], [-4, -1, 6, -2, 0, 0, 0, 0, -1, 0, -12, -1, 1, -2, 2, -2], [2, -1, 0, 2, -3, 2, -2, -3, 1, -2, 0, -1, -4, 3, -3, 1], [-2, 0, -1, -1, 2, -1, 1, 1, -1, 1, 2, 0, 2, -2, 2, -1], [0, 6, 0, 0, 0, 0, -6, 0, 6, 0, 0, -1, -1, -1, 2, 0], [1, 1, 0, 1, -5, 1, -2, 0, 3, -2, 1, 1, -3, 4, -4, 2], [0, -3, 0, 0, 0, 0, -3, 0, 1, -2, 0, -4, -6, 4, -2, 0], [-4, -1, 6, -4, 0, 2, 1, 0, -2, 1, -6, -1, 2, -3, 3, -2], [2, 1, -14, -3, 1, -4, 2, 2, -1, 2, 7, 1, 3, -2, 2, 0], [0, -5, 0, 0, 0, 0, -5, 0, 1, -4, 0, 1, -4, -1, -5, 0], [8, -2, -2, 0, -8, 4, -4, -4, 2, -4, 4, -2, -6, 4, -4, 0], [0, -2, 0, 0, 0, 0, 2, 0, -2, 0, 0, -2, -4, -2, 6, 0], [0, 3, 0, 0, 0, 0, -3, 0, 6, 6, 0, 1, 1, -2, 1, 0], [0, -2, 4, 0, 0, 4, 0, -4, -2, 0, 0, -2, -2, 0, 0, 0], [0, -5, 0, 0, 0, 0, 2, 0, -5, -2, 0, -1, 1, 3, -3, 0], [5, -1, 0, -1, -7, 5, -4, 0, 3, -4, 2, -1, -3, 2, -2, -2], [0, -1, 5, 0, 2, 10, 1, -2, -2, 1, 5, -1, 0, -1, 1, 0], [2, 1, 8, 2, 0, -8, -2, 4, 3, -2, 0, 1, 1, 0, 0, -2], [0, 4, 0, 0, 0, 0, 2, 0, 4, -2, 0, 0, 0, -4, 4, 0], [0, 2, 0, 0, 0, 6, 2, 0, 0, 2, 0, 2, 0, 2, -2, 4], [0, 4, 0, 0, 0, 0, -5, 0, 1, -1, 0, 2, 1, 1, -1, 0], [0, 0, 0, 0, 0, 0, -3, 0, 3, 3, 0, -3, 3, 0, 3, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -5, 1, -4, 0], [1, 0, 2, -2, 0, 0, 2, -2, -2, 2, 0, 0, 0, 0, 0, 2], [-4, 4, -1, 2, 7, -5, 3, 7, 1, 3, 1, 4, 6, -2, 2, 1], [0, -3, 0, 0, 0, 0, -2, 0, 5, -5, 0, 3, 1, 2, -1, 0], [0, 9, 0, 0, 0, 0, 4, 0, -9, 4, 0, 2, 2, 1, 1, 0], [0, -3, 0, 0, 0, 0, 3, 0, -3, 0, 0, 5, -1, 5, -4, 0], [-3, -3, 0, -3, 5, -3, 1, 0, -4, 1, -4, -3, 4, -7, 7, -6], [0, 0, 0, 0, 0, 0, -4, 0, 0, -4, 0, 0, 0, 1, 1, 0], [0, -7, 0, 0, 0, 0, 6, 0, -7, -6, 0, 1, -1, 4, -4, 0], [-4, 0, -12, 4, 0, 4, -2, 0, 2, -2, 6, 0, -2, 2, -2, 0], [4, 1, 0, 1, -1, 4, 0, 0, 1, 0, 5, 1, -1, 2, -2, 2], [0, 6, 0, 0, 0, 0, 6, 0, 3, 9, 0, -2, 2, 2, 4, 0], [0, -1, 0, 0, 0, 0, 1, 0, 2, -3, 0, 0, 5, 0, -5, 0], [0, 8, 0, 0, 0, 0, -7, 0, 8, 7, 0, 0, 0, -6, 6, 0], [0, 4, 0, 0, 0, 0, -4, 0, 4, 0, 0, 0, -2, 0, 2, 0], [0, -1, 0, 0, 0, 0, 10, 0, -9, 9, 0, 9, 5, 4, -5, 0], [2, 2, 0, 2, 6, 2, 4, 0, -2, 4, -6, 2, 2, 0, 0, 4], [8, -2, 16, 6, -2, -4, -4, -4, 2, -4, -8, -2, -6, 4, -4, 0], [0, -2, 7, 0, 1, -6, -1, -1, -1, -1, 7, -2, 0, -2, 2, -3], [18, 4, 7, 6, 5, -14, 1, 5, 3, 1, -7, 4, 2, 2, -2, 3], [0, 1, 0, 0, 0, 0, 2, 0, -3, 3, 0, 3, -2, 5, 2, 0], [0, -7, 0, 0, 0, 0, 0, 0, -7, -7, 0, 1, 3, -4, 3, 0], [6, 1, 1, 3, 0, -17, -3, 5, 4, -3, 0, 1, 1, 0, 0, -3], [0, -2, 0, 0, 0, 0, -3, 0, 5, -5, 0, -10, 3, -13, -3, 0], [0, -6, 0, 0, 6, -2, 0, -6, -6, 0, 0, -6, 0, -6, 6, -6], [-5, -3, 3, -9, 6, -3, 3, 3, -6, 3, -6, -3, 9, -12, 12, -9], [0, -4, 0, 0, 0, 0, 4, 0, -4, 0, 0, 2, -2, 2, 0, 0], [0, 6, 0, 6, 4, 0, 5, 0, 1, 5, -8, 6, -1, 7, -7, 12], [0, 12, 0, 0, 0, 0, -3, 0, 12, 3, 0, -7, 7, -11, 11, 0], [-8, 3, -13, -8, 10, -6, 7, 10, -4, 7, 13, 3, 14, -11, 11, -4], [0, 1, 0, 0, 0, 0, 1, 0, 5, 6, 0, -1, 3, 1, 4, 0], [0, -2, 0, 0, 0, 0, 2, 0, -5, 3, 0, 2, 6, 2, -8, 0], [6, -4, -4, -4, -4, 2, 0, -8, -4, 0, 2, -4, -4, 0, 0, 0], [-14, 3, 2, -2, 0, 24, 2, 4, 1, 2, 0, 3, 3, 0, 0, 2], [0, -4, 0, 0, 0, 0, 5, 0, -4, -5, 0, 4, -4, -1, 1, 0], [0, -2, 0, 0, 0, 0, -8, 0, 10, -10, 0, -6, 0, -6, 0, 0], [-3, -3, 0, -3, 3, -3, 0, 0, -3, 0, 9, -3, 3, -6, 6, -6], [7, -4, -8, 4, 0, -10, -4, -4, 0, -4, 0, -4, -4, 0, 0, -4], [-10, -4, 2, 6, -4, 18, -5, -8, 1, -5, -1, -4, -9, 5, -5, 0], [0, 10, 0, 0, 0, 0, 6, 0, 4, 4, 0, 5, -3, -2, -3, 0], [0, 5, 2, 0, -1, 0, 4, 1, 1, 4, 2, 5, 0, 5, -5, 9], [0, 3, 0, 0, 0, 0, 0, 0, -3, 0, 0, 8, 8, -4, -4, 0], [0, 4, 0, 0, 0, 0, -3, 0, 7, 7, 0, 4, -1, -3, -1, 0], [-18, 1, 3, -1, 6, -3, 3, 3, -2, 3, -6, 1, 5, -4, 4, -1], [-18, -6, -9, -6, -9, 18, -3, -9, -3, -3, 9, -6, -6, 0, 0, -3], [0, -2, -3, 0, -3, 4, -5, 3, 3, -5, -3, -2, 0, -2, 2, -7], [0, 3, 0, 0, 0, 0, 2, 0, -3, 2, 0, -3, -3, -8, -8, 0], [0, 5, 0, 0, 0, 0, -5, 0, -1, 6, 0, -4, 7, -4, -3, 0], [0, 6, 0, 0, 0, 0, -1, 0, -6, -1, 0, 0, 0, 7, 7, 0], [0, 0, 0, 0, 0, 0, -2, 0, 0, 2, 0, 10, -10, 7, -7, 0], [20, 2, -4, 0, 8, -4, 4, 4, -2, 4, 8, 2, 6, -4, 4, 0], [-11, -3, -6, -3, -3, 17, 0, -6, -3, 0, 3, -3, -3, 0, 0, 0], [0, -7, 8, 6, 0, 8, -6, -8, -1, -6, 0, -7, -7, 0, 0, -6], [0, 3, 0, 0, 0, 0, -3, 0, 6, -3, 0, 5, -7, 5, 2, 0], [-11, 1, 0, 1, -1, -11, 0, 0, 1, 0, 11, 1, -1, 2, -2, 2], [0, 4, 1, 0, -5, 14, -1, 5, 5, -1, 1, 4, 0, 4, -4, 3], [0, 8, 0, 0, 0, 0, -5, 0, 8, 5, 0, -4, 4, 5, -5, 0], [0, 3, 0, 0, 0, 0, 0, 0, 3, 3, 0, -2, -2, 4, -2, 0], [0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 0, 2, 2, 0, 0, 0], [16, -4, 4, -8, -4, -4, 0, -4, -4, 0, -4, -4, 0, -4, 4, -4], [0, -1, 0, 0, 0, 0, 2, 0, -1, 1, 0, 1, -7, 8, 7, 0], [0, -10, 0, 0, 0, 0, -10, 0, 4, -6, 0, 4, 6, -4, 2, 0], [6, -3, -2, -8, 4, -2, 2, 2, -5, 2, 4, -3, 7, -10, 10, -8], [-18, 0, 3, 6, -3, 12, -3, -3, 3, -3, -3, 0, -6, 6, -6, 3], [0, 6, 0, 0, 0, 0, -1, 0, -5, 5, 0, -13, -9, -4, 9, 0], [5, 6, 6, 9, 6, -3, 3, 3, 3, 3, -12, 6, 0, 6, -6, 9], [-4, -4, 0, -4, 10, -4, 3, 0, -7, 3, 1, -4, 7, -11, 11, -8], [0, -11, 0, 0, 0, 0, -11, 0, 4, -7, 0, 6, 0, -6, -6, 0], [0, -3, 0, 0, 0, 0, 6, 0, 3, 6, 0, -7, -7, 8, 8, 0], [20, -6, -2, -4, -10, 0, -4, -10, -2, -4, 2, -6, -8, 2, -2, -2], [8, -4, 0, -4, 8, 8, 2, 0, -6, 2, 20, -4, 6, -10, 10, -8], [0, 4, 0, 0, 0, 0, 4, 0, -6, -2, 0, -3, 7, 3, 10, 0], [12, 1, 10, 1, 1, -14, 0, 2, 1, 0, -5, 1, 1, 0, 0, 0], [0, -9, 0, 0, 0, 0, 0, 0, -9, -9, 0, 9, -6, -3, -6, 0], [-5, 1, -9, 1, 0, 7, -1, 3, 2, -1, 0, 1, 1, 0, 0, -1], [0, -4, 0, 0, 0, 0, 8, 0, -4, 4, 0, 1, -1, 2, 1, 0], [14, -1, -18, 2, 0, -28, -2, 0, 1, -2, 0, -1, -1, 0, 0, -2], [14, 0, 12, 0, 0, -14, 0, 0, 0, 0, -6, 0, 0, 0, 0, 0], [0, 9, 0, 0, 0, 0, 8, 0, -9, 8, 0, -3, -3, 4, 4, 0], [0, -4, 0, 0, 0, 0, -4, 0, 8, -8, 0, -6, 0, -6, 0, 0], [0, -4, 0, 0, 0, 0, -4, 0, 5, 1, 0, 2, -8, -2, -10, 0], [11, 3, 9, 9, -6, 3, -3, -3, 6, -3, -18, 3, -9, 12, -12, 9], [4, 2, 28, 16, -4, 2, -6, -4, 8, -6, -28, 2, -12, 14, -14, 8], [0, 7, -7, 0, -7, -7, 0, 7, 7, 0, -7, 7, 0, 7, -7, 7], [-14, 3, -6, 6, 0, 0, 0, 0, 3, 0, 12, 3, -3, 6, -6, 6], [0, 2, 0, 0, 0, 0, -2, 0, 14, -12, 0, -6, 2, -6, 4, 0], [0, 14, 0, 0, 0, 0, 14, 0, 0, 14, 0, 4, 10, -4, 6, 0], [0, 3, 0, 0, 0, 0, 10, 0, -3, 10, 0, 7, 7, 3, 3, 0], [0, 12, 0, 0, 0, 0, 12, 0, -1, 11, 0, 9, 1, -9, -8, 0], [0, -6, 0, 0, 0, 0, 6, 0, 0, -6, 0, 11, -1, 11, -10, 0], [9, -3, 21, -3, 0, -9, 3, -9, -6, 3, 0, -3, -3, 0, 0, 3], [0, 11, 0, 0, 0, 0, -10, 0, 11, 10, 0, 2, -2, -2, 2, 0], [-6, 6, 0, 6, -6, -6, 0, 0, 6, 0, -6, 6, -6, 12, -12, 12], [0, -9, -6, 0, 6, -8, -3, -6, -6, -3, -6, -9, 0, -9, 9, -12], [12, -6, -6, 0, 0, -12, 0, -12, -6, 0, 0, -6, -6, 0, 0, 0], [0, -14, 0, 0, 0, 0, -7, 0, -14, 7, 0, 9, -9, 5, -5, 0], [0, -4, 0, 0, 0, 0, 0, 0, -4, -4, 0, -2, 6, -4, 6, 0], [0, 6, 0, 0, 0, 0, 5, 0, -11, 11, 0, -1, 0, -1, 0, 0], [0, -16, 0, 0, 0, 0, -6, 0, -10, -10, 0, -6, 2, 4, 2, 0], [0, -1, 0, 0, 0, 0, -1, 0, 4, 3, 0, -2, 0, 2, 2, 0], [-1, 3, -8, -7, 0, 3, 7, -1, -4, 7, 0, 3, 3, 0, 0, 7], [0, 0, 6, 0, 0, 10, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0], [0, -12, 0, 0, 0, 0, -18, 0, 12, -18, 0, -6, -6, -6, -6, 0], [1, -5, -5, -3, -14, 7, -7, -7, 2, -7, 10, -5, -9, 4, -4, -3], [0, -5, 0, 0, 0, 0, 5, 0, -8, 3, 0, 7, -4, 7, -3, 0], [23, -3, 18, 9, -3, -17, -6, -6, 3, -6, -9, -3, -9, 6, -6, 0], [8, -1, 0, -1, 1, 8, 0, 0, -1, 0, 19, -1, 1, -2, 2, -2], [23, 1, 2, 1, 2, -1, 1, 1, 0, 1, -4, 1, 1, 0, 0, 1], [0, -4, 0, 0, 0, 0, 6, 0, -10, -10, 0, -10, 4, 6, 4, 0], [0, -12, 0, 0, 0, 0, 14, 0, -12, -14, 0, -2, 2, 6, -6, 0], [0, -4, 0, 0, 0, 0, 4, 0, -1, -3, 0, -6, 8, -6, -2, 0], [1, -5, 0, -5, 5, 1, 0, 0, -5, 0, -1, -5, 5, -10, 10, -10], [9, -3, 39, -3, 0, -9, 3, -9, -6, 3, 0, -3, -3, 0, 0, 3], [0, -4, -5, 0, 1, -5, -3, -1, -1, -3, -5, -4, 0, -4, 4, -7], [0, 3, 0, 0, 0, 0, 11, 0, -3, 11, 0, 0, 0, 4, 4, 0], [-14, 0, 11, 10, -5, 12, -5, -5, 5, -5, -11, 0, -10, 10, -10, 5], [0, -2, 0, 0, 0, 0, -6, 0, 4, 4, 0, 2, -6, 4, -6, 0], [10, -8, -8, -18, 4, -2, 2, 2, -10, 2, 16, -8, 12, -20, 20, -18], [0, 8, 0, 0, 0, 0, -13, 0, 5, -5, 0, 3, 6, -3, -6, 0]];
    aps := ConvertToHeckeField(raw_aps);
    chi := MakeCharacter_126_m_Hecke(Universe(aps));
    return ExtendMultiplicatively(weight, aps, chi);
end function;


// To make the newform (type ModFrm), type "MakeNewformModFrm_126_2_m_a();".
// This may take a long time!  To see verbose output, uncomment the SetVerbose lines below.
// The precision argument determines an initial guess on how many Fourier coefficients to use.
// This guess is increased enough to uniquely determine the newform.
function MakeNewformModFrm_126_2_m_a(:prec:=16)
    chi := MakeCharacter_126_m();
    f_vec := qexpCoeffs();
    Kf := Universe(f_vec);
    // SetVerbose("ModularForms", true);
    // SetVerbose("ModularSymbols", true);
    S := CuspidalSubspace(ModularForms(chi, 2));
    S := BaseChange(S, Kf);
    maxprec := NextPrime(997) - 1;
    while true do
        trunc_vec := Vector(Kf, [0] cat [f_vec[i]: i in [1..prec]]);
        B := Basis(S, prec + 1);
        S_basismat := Matrix([AbsEltseq(g): g in B]);
        if Rank(S_basismat) eq Min(NumberOfRows(S_basismat), NumberOfColumns(S_basismat)) then
            S_basismat := ChangeRing(S_basismat,Kf);
            f_lincom := Solution(S_basismat,trunc_vec);
            f := &+[f_lincom[i]*Basis(S)[i] : i in [1..#Basis(S)]];
            return f;
        end if;
        error if prec eq maxprec, "Unable to distinguish newform within newspace";
        prec := Min(Ceiling(1.25 * prec), maxprec);
    end while;
end function;


// To make the Hecke irreducible modular symbols subspace (type ModSym)
// containing the newform, type "MakeNewformModSym_126_2_m_a();".
// This may take a long time!  To see verbose output, uncomment the SetVerbose line below.
// The default sign is -1.  You can change this with the optional parameter "sign".
function MakeNewformModSym_126_2_m_a( : sign := -1)
    R<x> := PolynomialRing(Rationals());
    chi := MakeCharacter_126_m();
    // SetVerbose("ModularSymbols", true);
    Snew := NewSubspace(CuspidalSubspace(ModularSymbols(chi,2,sign)));
    Vf := Kernel([],Snew);
    return Vf;
end function;