# SageMath code for working with modular form 325.3.t.a # Compute space of new eigenforms: from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(325, base_ring=CyclotomicField(12)) chi = DirichletCharacter(H, H._module([0, 7])) N = Newforms(chi, 3, names="a") # select newform: traces = [4,2,2,-6,0,10,-16,6] f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(8)] == traces) # q-expansion: f.q_expansion() # note that sage often uses an isomorphic number field