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 A038023 #10 Dec 19 2015 09:51:15 %S A038023 0,0,0,0,0,0,3,6,0,4,96,214,128,64,38,54248,83925,54223,28254,10223, %T A038023 1894 %N A038023 Triangle: T(n,k), k<=n: commutative groupoids with a nontrivial symmetry with n elements and k idempotents. %H A038023 <a href="/index/Gre#groupoids">Index entries for sequences related to groupoids</a> %F A038023 Difference of A038021 and A038022. %Y A038023 Cf. A001329, A001425, A030259, A030262, A030265. %K A038023 nonn,tabl,more %O A038023 0,7 %A A038023 _Christian G. Bower_, May 15 1998