# SageMath code for working with modular form 1280.2.n.b # Compute space of new eigenforms: from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(1280, base_ring=CyclotomicField(4)) chi = DirichletCharacter(H, H._module([2, 0, 1])) N = Newforms(chi, 2, names="a") # select newform: f = N[0] # Warning: the index may be different # q-expansion: f.q_expansion() # note that sage often uses an isomorphic number field