I am trying to do some experimentation with the values of Thompson series, but I have having a hard time finding a table that has these Thompson series with as many terms as I'd like. The tables I've seen only give me the required Head character values up to the $q^{10}$ term.

Can someone point me to a resource that either has more terms, or (even better), a resource that might help me compute them myself in sage?

Thanks a lot for any help.