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 A036298 #11 Jul 08 2025 21:44:01 %S A036298 0,1,2,720,620448401733239439360000 %N A036298 (n!)!, n>0 (note that A000197 is the correct version of this sequence, with a(0) = 1, not 0). %K A036298 nonn,easy %O A036298 0,3 %A A036298 _N. J. A. Sloane_