# SageMath code for working with modular form 9248.2.a.y


# Compute space of new eigenforms: 
from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(9248, base_ring=CyclotomicField(2))
chi = DirichletCharacter(H, H._module([0, 0, 0]))
N = Newforms(chi, 2, names="a")

# select newform: 
traces = [4,0,-2,0,2,0,-6,0,6,0,0,0,2,0,8,0,0,0,-6,0,12,0,-6,0,2,0,-8,
0,2,0,0,0,-10,0,-14,0,0,0,-26,0,-16,0,8,0,-20,0,8,0,14,0,0,0,-6,0,-22,
0,6,0,-16,0,20,0,-24,0,4,0,0,0,-4,0,0,0,4,0,-8,0,-2,0,-24,0,32,0,26,0,
0,0,-10,0,0,0,-32,0,26,0,32,0,-22,0,50,0,-4,0,-32,0,-14,0,-32,0,28,0,32,
0,10,0,10,0,2,0,0,0,-8,0,-8,0,36,0,-8,0,-46,0,-16,0,4,0,38,0,24,0,-22,
0,2,0,-2,0,-20]
f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(145)] == traces)

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