Properties

Label 21.8.a.c
Level $21$
Weight $8$
Character orbit 21.a
Self dual yes
Analytic conductor $6.560$
Analytic rank $0$
Dimension $2$
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] = [21,8,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, 8); 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, 8, names="a")
 
Level: \( N \) \(=\) \( 21 = 3 \cdot 7 \)
Weight: \( k \) \(=\) \( 8 \)
Character orbit: \([\chi]\) \(=\) 21.a (trivial)

Newform invariants

Copy content comment:select newform
 
Copy content sage:traces = [2,12] 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: \(6.56008553517\)
Analytic rank: \(0\)
Dimension: \(2\)
Coefficient field: \(\Q(\sqrt{67}) \)
Copy content comment:defining polynomial
 
Copy content gp:f.mod \\ as an extension of the character field
 
Defining polynomial: \( x^{2} - 67 \) Copy content Toggle raw display
Coefficient ring: \(\Z[a_1, a_2]\)
Coefficient ring index: \( 2 \)
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 \(\beta = 2\sqrt{67}\). We also show the integral \(q\)-expansion of the trace form.

\(f(q)\) \(=\) \( q + (\beta + 6) q^{2} - 27 q^{3} + (12 \beta + 176) q^{4} + (8 \beta - 12) q^{5} + ( - 27 \beta - 162) q^{6} - 343 q^{7} + (120 \beta + 3504) q^{8} + 729 q^{9} + (36 \beta + 2072) q^{10} + ( - 280 \beta + 1062) q^{11}+ \cdots + ( - 204120 \beta + 774198) q^{99}+O(q^{100}) \) Copy content Toggle raw display
\(\operatorname{Tr}(f)(q)\) \(=\) \( 2 q + 12 q^{2} - 54 q^{3} + 352 q^{4} - 24 q^{5} - 324 q^{6} - 686 q^{7} + 7008 q^{8} + 1458 q^{9} + 4144 q^{10} + 2124 q^{11} - 9504 q^{12} - 1084 q^{13} - 4116 q^{14} + 648 q^{15} + 61312 q^{16} - 29256 q^{17}+ \cdots + 1548396 q^{99}+O(q^{100}) \) 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
−8.18535
8.18535
−10.3707 −27.0000 −20.4485 −142.966 280.009 −343.000 1539.52 729.000 1482.65
1.2 22.3707 −27.0000 372.448 118.966 −604.009 −343.000 5468.48 729.000 2661.35
\(n\): 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 21.8.a.c 2
3.b odd 2 1 63.8.a.c 2
4.b odd 2 1 336.8.a.p 2
5.b even 2 1 525.8.a.d 2
7.b odd 2 1 147.8.a.d 2
7.c even 3 2 147.8.e.f 4
7.d odd 6 2 147.8.e.e 4
21.c even 2 1 441.8.a.h 2
    
        By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
21.8.a.c 2 1.a even 1 1 trivial
63.8.a.c 2 3.b odd 2 1
147.8.a.d 2 7.b odd 2 1
147.8.e.e 4 7.d odd 6 2
147.8.e.f 4 7.c even 3 2
336.8.a.p 2 4.b odd 2 1
441.8.a.h 2 21.c even 2 1
525.8.a.d 2 5.b even 2 1

Hecke kernels

This newform subspace can be constructed as the kernel of the linear operator \( T_{2}^{2} - 12T_{2} - 232 \) acting on \(S_{8}^{\mathrm{new}}(\Gamma_0(21))\). Copy content Toggle raw display

Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ \( T^{2} - 12T - 232 \) Copy content Toggle raw display
$3$ \( (T + 27)^{2} \) Copy content Toggle raw display
$5$ \( T^{2} + 24T - 17008 \) Copy content Toggle raw display
$7$ \( (T + 343)^{2} \) Copy content Toggle raw display
$11$ \( T^{2} - 2124 T - 19883356 \) Copy content Toggle raw display
$13$ \( T^{2} + 1084 T - 21935228 \) Copy content Toggle raw display
$17$ \( T^{2} + 29256 T - 287563248 \) Copy content Toggle raw display
$19$ \( T^{2} + 25816 T - 160026224 \) Copy content Toggle raw display
$23$ \( T^{2} + \cdots + 1166614596 \) Copy content Toggle raw display
$29$ \( T^{2} + \cdots + 1307845988 \) Copy content Toggle raw display
$31$ \( T^{2} + \cdots + 43635483648 \) Copy content Toggle raw display
$37$ \( T^{2} + 28428 T - 887182812 \) Copy content Toggle raw display
$41$ \( T^{2} + \cdots + 127701459200 \) Copy content Toggle raw display
$43$ \( T^{2} + \cdots - 71585337968 \) Copy content Toggle raw display
$47$ \( T^{2} + \cdots - 268603868016 \) Copy content Toggle raw display
$53$ \( T^{2} + \cdots - 263627226684 \) Copy content Toggle raw display
$59$ \( T^{2} + \cdots - 345691376064 \) Copy content Toggle raw display
$61$ \( T^{2} + \cdots + 504531767044 \) Copy content Toggle raw display
$67$ \( T^{2} + \cdots - 11591287019456 \) Copy content Toggle raw display
$71$ \( T^{2} + \cdots - 3929864540796 \) Copy content Toggle raw display
$73$ \( T^{2} + \cdots - 10787980935996 \) Copy content Toggle raw display
$79$ \( T^{2} + \cdots - 26777501165936 \) Copy content Toggle raw display
$83$ \( T^{2} + \cdots - 7065815171184 \) Copy content Toggle raw display
$89$ \( T^{2} + \cdots - 6900412319488 \) Copy content Toggle raw display
$97$ \( T^{2} + \cdots + 164115180472068 \) Copy content Toggle raw display
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