This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A048632 #8 Sep 30 2022 13:23:30 %S A048632 0,0,0,0,0,0,448,3136,25088,238080,2780160,32409600,439263232, %T A048632 5793579008,84589174784,1277254508544,20436072136704,347559326515200, %U A048632 6269816107433984,119673237950431232,2402480754490605568,50578266728651816960,1116823836321860550656 %N A048632 Differences between factorials and Xfactorials: A048631 - A000142. %F A048632 a(n) = n! - Xfactorial(n). %Y A048632 Cf. A000142, A048631. %K A048632 easy,nonn %O A048632 0,7 %A A048632 _Antti Karttunen_, Jul 14 1999