# SageMath code for working with modular form 575.2.p.b # Compute space of new eigenforms: from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(575, base_ring=CyclotomicField(22)) chi = DirichletCharacter(H, H._module([11, 16])) N = Newforms(chi, 2, names="a") # select newform: traces = [20,0,0,6] f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(4)] == traces) # q-expansion: f.q_expansion() # note that sage often uses an isomorphic number field