magma://Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code
chi := DirichletCharacter("7650.1");
S:= CuspForms(chi, 2);
N := Newforms(S);
sage:from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(7650, base_ring=CyclotomicField(2))
chi = DirichletCharacter(H, H._module([0, 0, 0]))
N = Newforms(chi, 2, names="a")
sage:traces = [1,-1,0,1,0,0,1,-1,0,0,-3,0,4,-1,0,1,1,0,5,0,0,3,0,0,0,-4,0,1,
6]
f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(29)] == traces)
gp:f = lf[1] \\ Warning: the index may be different