gp:[N,k,chi] = [20691,2,Mod(1,20691)]
mf = mfinit([N,k,chi],0)
lf = mfeigenbasis(mf)
sage:from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(20691, base_ring=CyclotomicField(2))
chi = DirichletCharacter(H, H._module([0, 0, 0]))
N = Newforms(chi, 2, names="a")
magma://Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code
chi := DirichletCharacter("20691.1");
S:= CuspForms(chi, 2);
N := Newforms(S);
Newform invariants
sage:traces = [1,2,0,2,0,0,2,0,0,0,0,0,5,4,0,-4,-3,0,-1,0,0,0,-6,0,-5,10,0,
4,8,0,-2,-8,0,-6,0,0,-8,-2,0,0,2,0,-2,0,0,-12,4,0,-3,-10,0,10,-3,0,0,0,
0,16,-13,0,2,-4,0,-8,0,0,2,-6,0,0,-7,0,14,-16,0,-2,0,0,-11,0,0,4,-9,0,
0,-4,0,0,-13,0,10,-12,0,8,0,0,-18,-6,0,-10]
f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(None)] == traces)
gp:f = lf[1] \\ Warning: the index may be different
sage:f.q_expansion() # note that sage often uses an isomorphic number field
gp:mfcoefs(f, 20)
p |
Sign
|
3 |
+1 |
11 |
+1 |
19 |
+1 |
Inner twists of this newform have not been computed.
Twists of this newform have not been computed.