This is some project euler code I have worked on, and a first foray for me into using github. Some code is snipped from the discussion forums.Some pieces in CL, some in Python, early portions in C.Typically, my original method will not have a letter appended. So p10.lisp is something I wrote, while p12a.lisp is something I read in the forum.I started working these in C as being the first tool I learned to use fairly well. When I found that overflow became a significant issue in many of the  PE type problems, I moved to lisp. I did a handful in Python mainly as a way of getting a feel for the language (required language for the first year programmingsequence at UIC's math department.) Really, apart from the snippets culled from the forums, the code I wrote here is pretty embarassing. The first problem I found was that I was missing all the important abstractions in CL, and just using do for everything.I think I also had the uphill struggle of writing significant portions of the lisp code while reading SICP and the little lisper, so there's a fair number of 'schemisms' scattered throughout, when CL had library facilities to do just what I wanted. Imagine how long and troublesome the language is if you don't have remove-if and remove-if-not as builtins...Update : 12/4/2012during a slight confusion of git tree manipulation, all the date/timestamps have been reset. It's unfortunate, but the commit history still preserves the important part.Note : the file util.lisp contains general purpose functions which are referenced in files but not perhaps explicitly loaded. My working environment typically has at least number-theory.lisp (from the number-theory repo) loaded, and often util.lisp.