For geometrical reasons, I'm confident that there exists a weight 4 eigenform with trivial nebentypus whose p-th Fourier coefficients c(p) satisfy the following for primes p >11: (1) c(13) = 14 and c(19) = 43 (2) c(p) is a rational integer when p = 1 mod 3 (3) c(p) is a rational integer times sqrt(55) when p = 2 mod 3.
For reasons connected to ramification, the prime factors of the level N are very likely to be a subset of {2, 3, 5, 7, 11}. I am searching for this eigenform using sage commands such as G=DirichletGroup(825,CyclotomicField(1)); X=G.list(); Y=X [0] D=ModularSymbols(Y, 4, sign=1).cuspidal_subspace().new_subspace ().decomposition() D[4].q_eigenform( 14,'a') Such a search becomes prohibitively slow once the level N gets near 1000. I have a feeling that my search will be over as soon as I find a weight 4 eigenform with c(13) = 0 mod 7. So my question is this: If instead of searching as above for cases where c(13) = 14, all I need to find is a case where c(13) = 0 mod 7, is there a *faster* sage implementation, e.g., using a base field GF(7)? Thanks. rje --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---