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 A038019 #10 Dec 19 2015 09:50:31 %S A038019 1,0,1,1,4,1,969,1431,729,108,56615456,75491208,37741600,8386560, %T A038019 697501 %N A038019 Triangle: T(n,k), k<=n: groupoids with no symmetry with n elements and k idempotents. %H A038019 <a href="/index/Gre#groupoids">Index entries for sequences related to groupoids</a> %Y A038019 Cf. A001329, A030248, A030251, A030271. %K A038019 nonn,tabl,more %O A038019 0,5 %A A038019 _Christian G. Bower_, May 15 1998