Here is the link to The On-Line Encyclopedia of Integer Sequences as discussed in Bellos’ book Alex’s adventures in Numberland I’ve been reading recently. In one section he discusses number sequences and refers to this site by Neil Slone. Not only can you look up 1000s of sequences you can also have them played to you as a midi sequence here http://oeis.org/play.html.

And here is a link to the golden mean guage where you can create your own