Properties

Label 21.18.a.c
Level $21$
Weight $18$
Character orbit 21.a
Self dual yes
Analytic conductor $38.477$
Analytic rank $0$
Dimension $4$
CM no
Inner twists $1$

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Newspace parameters

Copy content comment:Compute space of new eigenforms
 
Copy content gp:[N,k,chi] = [21,18,Mod(1,21)] mf = mfinit([N,k,chi],0) lf = mfeigenbasis(mf)
 
Copy content magma://Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code chi := DirichletCharacter("21.1"); S:= CuspForms(chi, 18); N := Newforms(S);
 
Copy content sage:from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(21, base_ring=CyclotomicField(2)) chi = DirichletCharacter(H, H._module([0, 0])) N = Newforms(chi, 18, names="a")
 
Level: \( N \) \(=\) \( 21 = 3 \cdot 7 \)
Weight: \( k \) \(=\) \( 18 \)
Character orbit: \([\chi]\) \(=\) 21.a (trivial)

Newform invariants

Copy content comment:select newform
 
Copy content sage:traces = [4,-18] f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(2)] == traces)
 
Copy content gp:f = lf[1] \\ Warning: the index may be different
 
Self dual: yes
Analytic conductor: \(38.4766383424\)
Analytic rank: \(0\)
Dimension: \(4\)
Coefficient field: \(\mathbb{Q}[x]/(x^{4} - \cdots)\)
Copy content comment:defining polynomial
 
Copy content gp:f.mod \\ as an extension of the character field
 
Defining polynomial: \( x^{4} - x^{3} - 102516x^{2} - 1667140x + 2022689200 \) Copy content Toggle raw display
Coefficient ring: \(\Z[a_1, \ldots, a_{5}]\)
Coefficient ring index: \( 2^{8}\cdot 3^{2}\cdot 5\cdot 7 \)
Twist minimal: yes
Fricke sign: \(-1\)
Sato-Tate group: $\mathrm{SU}(2)$

$q$-expansion

Copy content comment:q-expansion
 
Copy content sage:f.q_expansion() # note that sage often uses an isomorphic number field
 
Copy content gp:mfcoefs(f, 20)
 

Coefficients of the \(q\)-expansion are expressed in terms of a basis \(1,\beta_1,\beta_2,\beta_3\) for the coefficient ring described below. We also show the integral \(q\)-expansion of the trace form.

\(f(q)\) \(=\) \( q + ( - \beta_1 - 4) q^{2} - 6561 q^{3} + (\beta_{2} + 59 \beta_1 + 73952) q^{4} + (\beta_{3} - 8 \beta_{2} + \cdots + 213032) q^{5} + (6561 \beta_1 + 26244) q^{6} + 5764801 q^{7} + ( - 48 \beta_{3} - 282 \beta_{2} + \cdots - 11903552) q^{8}+ \cdots + (30175751421 \beta_{3} + \cdots + 11\!\cdots\!30) q^{99}+O(q^{100}) \) Copy content Toggle raw display
\(\operatorname{Tr}(f)(q)\) \(=\) \( 4 q - 18 q^{2} - 26244 q^{3} + 295924 q^{4} + 851508 q^{5} + 118098 q^{6} + 23059204 q^{7} - 47595096 q^{8} + 172186884 q^{9} + 258095940 q^{10} + 1082146572 q^{11} - 1941557364 q^{12} + 2607537464 q^{13}+ \cdots + 46\!\cdots\!12 q^{99}+O(q^{100}) \) Copy content Toggle raw display

Basis of coefficient ring in terms of a root \(\nu\) of \( x^{4} - x^{3} - 102516x^{2} - 1667140x + 2022689200 \) : Copy content Toggle raw display

\(\beta_{1}\)\(=\) \( 2\nu \) Copy content Toggle raw display
\(\beta_{2}\)\(=\) \( 4\nu^{2} - 102\nu - 205008 \) Copy content Toggle raw display
\(\beta_{3}\)\(=\) \( ( \nu^{3} - 135\nu^{2} - 59622\nu + 5607524 ) / 6 \) Copy content Toggle raw display
\(\nu\)\(=\) \( ( \beta_1 ) / 2 \) Copy content Toggle raw display
\(\nu^{2}\)\(=\) \( ( \beta_{2} + 51\beta _1 + 205008 ) / 4 \) Copy content Toggle raw display
\(\nu^{3}\)\(=\) \( ( 24\beta_{3} + 135\beta_{2} + 126129\beta _1 + 5245984 ) / 4 \) Copy content Toggle raw display

Embeddings

For each embedding \(\iota_m\) of the coefficient field, the values \(\iota_m(a_n)\) are shown below.

For more information on an embedded modular form you can click on its label.

Copy content comment:embeddings in the coefficient field
 
Copy content gp:mfembed(f)
 
Label   \(\iota_m(\nu)\) \( a_{2} \) \( a_{3} \) \( a_{4} \) \( a_{5} \) \( a_{6} \) \( a_{7} \) \( a_{8} \) \( a_{9} \) \( a_{10} \)
1.1
290.929
148.366
−185.017
−253.278
−585.858 −6561.00 212158. −559169. 3.84381e6 5.76480e6 −4.75046e7 4.30467e7 3.27593e8
1.2 −300.731 −6561.00 −40632.6 685014. 1.97310e6 5.76480e6 5.16370e7 4.30467e7 −2.06005e8
1.3 366.034 −6561.00 2908.63 1.67136e6 −2.40155e6 5.76480e6 −4.69121e7 4.30467e7 6.11775e8
1.4 502.556 −6561.00 121490. −945700. −3.29727e6 5.76480e6 −4.81531e6 4.30467e7 −4.75267e8
\(n\): e.g. 2-40 or 990-1000
Significant digits:
Format:

Atkin-Lehner signs

\( p \) Sign
\(3\) \( +1 \)
\(7\) \( -1 \)

Inner twists

This newform does not admit any (nontrivial) inner twists.

Twists

       By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 21.18.a.c 4
3.b odd 2 1 63.18.a.c 4
    
        By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
21.18.a.c 4 1.a even 1 1 trivial
63.18.a.c 4 3.b odd 2 1

Hecke kernels

This newform subspace can be constructed as the kernel of the linear operator \( T_{2}^{4} + 18T_{2}^{3} - 409944T_{2}^{2} + 10056960T_{2} + 32409815040 \) acting on \(S_{18}^{\mathrm{new}}(\Gamma_0(21))\). Copy content Toggle raw display

Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ \( T^{4} + \cdots + 32409815040 \) Copy content Toggle raw display
$3$ \( (T + 6561)^{4} \) Copy content Toggle raw display
$5$ \( T^{4} + \cdots + 60\!\cdots\!00 \) Copy content Toggle raw display
$7$ \( (T - 5764801)^{4} \) Copy content Toggle raw display
$11$ \( T^{4} + \cdots + 38\!\cdots\!44 \) Copy content Toggle raw display
$13$ \( T^{4} + \cdots + 93\!\cdots\!40 \) Copy content Toggle raw display
$17$ \( T^{4} + \cdots - 42\!\cdots\!76 \) Copy content Toggle raw display
$19$ \( T^{4} + \cdots + 37\!\cdots\!44 \) Copy content Toggle raw display
$23$ \( T^{4} + \cdots + 51\!\cdots\!00 \) Copy content Toggle raw display
$29$ \( T^{4} + \cdots + 85\!\cdots\!36 \) Copy content Toggle raw display
$31$ \( T^{4} + \cdots - 58\!\cdots\!00 \) Copy content Toggle raw display
$37$ \( T^{4} + \cdots + 16\!\cdots\!84 \) Copy content Toggle raw display
$41$ \( T^{4} + \cdots - 47\!\cdots\!04 \) Copy content Toggle raw display
$43$ \( T^{4} + \cdots - 10\!\cdots\!60 \) Copy content Toggle raw display
$47$ \( T^{4} + \cdots - 92\!\cdots\!00 \) Copy content Toggle raw display
$53$ \( T^{4} + \cdots + 18\!\cdots\!44 \) Copy content Toggle raw display
$59$ \( T^{4} + \cdots + 13\!\cdots\!60 \) Copy content Toggle raw display
$61$ \( T^{4} + \cdots - 47\!\cdots\!84 \) Copy content Toggle raw display
$67$ \( T^{4} + \cdots - 52\!\cdots\!64 \) Copy content Toggle raw display
$71$ \( T^{4} + \cdots - 25\!\cdots\!00 \) Copy content Toggle raw display
$73$ \( T^{4} + \cdots + 87\!\cdots\!84 \) Copy content Toggle raw display
$79$ \( T^{4} + \cdots + 17\!\cdots\!96 \) Copy content Toggle raw display
$83$ \( T^{4} + \cdots - 73\!\cdots\!44 \) Copy content Toggle raw display
$89$ \( T^{4} + \cdots + 18\!\cdots\!84 \) Copy content Toggle raw display
$97$ \( T^{4} + \cdots - 47\!\cdots\!56 \) Copy content Toggle raw display
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