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 A347686 #3 Sep 18 2021 23:44:19 %S A347686 0,0,1,13,90,656,4862,39938,362122,3627433,39913180,478994407, %T A347686 6227001093,87178250333,1307674292294,20922789757983,355687427756494, %U A347686 6402373705060610,121645100407007344,2432902008172915083,51090942171702654311,1124000727777596134102,25852016738884946540910,620448401733239380526706,15511210043330985878651420 %N A347686 n! - A345882(n). %Y A347686 Cf. A345882. %K A347686 nonn %O A347686 1,4 %A A347686 _N. J. A. Sloane_, Sep 18 2021