# SageMath code for working with modular form 25410.2.a.cx


# Compute space of new eigenforms: 
from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(25410, base_ring=CyclotomicField(2))
chi = DirichletCharacter(H, H._module([0, 0, 0, 0]))
B = ModularForms(chi, 1).cuspidal_submodule().basis()
N = [B[i] for i in range(len(B))]

# Compute space of new eigenforms: 
from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(25410, base_ring=CyclotomicField(2))
chi = DirichletCharacter(H, H._module([0, 0, 0, 0]))
N = Newforms(chi, 2, names="a") 

# select newform: 
traces = [1,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,-4,1,-4,1,1,0,-6,1,1,0,1,1,0,
1,-6,1,0,-4,1,1,-6,-4,0,1,6,1,-4,0,1,-6,-4,1,1,1,-4,0,2,1,0,1,-4,0,10,
1,6,-6,1,1,0,0,-2,-4,-6,1,-12,1,-8,-6,1,-4,0,0,4,1,1,6,-4,1,-4,-4,0,0,
-6,1,0,-6,-6,-4,-4,1,-2,1,0,1]
f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(None)] == traces)

# q-expansion: 
f.q_expansion() # note that sage often uses an isomorphic number field