# SageMath code for working with modular form 23670.2.a.t # Compute space of new eigenforms: from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(23670, base_ring=CyclotomicField(2)) chi = DirichletCharacter(H, H._module([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(23670, base_ring=CyclotomicField(2)) chi = DirichletCharacter(H, H._module([0, 0, 0])) N = Newforms(chi, 2, names="a") # select newform: traces = [1,1,0,1,1,0,1,1,0,1,-1,0,-4,1,0,1,-8,0,0,1,0,-1,4,0,1,-4,0,1, 4,0,9,1,0,-8,1,0,2,0,0,1,0,0,-8,-1,0,4,-3,0,-6,1,0,-4,-9,0,-1,1,0,4,8, 0,-11,9,0,1,-4,0,-8,-8,0,1,10,0,-3,2,0,0,-1,0,10,1,0,0,12,0,-8,-8,0,-1, -1,0,-4,4,0,-3,0,0,2,-6,0,1] 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