Maybe it only has .5! in memory and it can calculate the others from that, but it doesn't want to do the integral for all values, because it will take too long. You can always evaluate the gamma integral to find 1.6! LMWapner wrote in message <1998052921112800.RAA28129@ladder03.news.aol.com>... >Thanks for the response. > >But why does the TI-83 compute 1.5! (via the gamma function) >and not 1.6! ? > >Thanks - Len