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 A144883 #8 Dec 28 2023 19:39:43 %S A144883 1,3,21,96,684,4320,35640,293760,2881440,29695680,345643200, %T A144883 4296499200,58518028800,851751936000,13338801100800,222145265664000, %U A144883 3934764739584000,73675580977152000,1455693852146688000,30238671742304256000,659012259039805440000 %N A144883 Second column (m=2) of triangle A144881 (S1hat(3)). %F A144883 a(n) = A144881(n+2,2), n>=0. %Y A144883 Cf. A144881, A001710 (first column), A144884 (third column). %K A144883 nonn,easy %O A144883 0,2 %A A144883 _Wolfdieter Lang_, Oct 09 2008