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 A058170 #6 Mar 30 2012 17:37:12 %S A058170 1,2,1,3,7,2,10,28,33,7,82,153,261,213,37,2511,1227,2266,2989,1709, %T A058170 263,600106,26033,24176,39176,38346,16306,2134 %N A058170 Triangle: Number of asymmetric semigroups of order n with k idempotents, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator). %H A058170 <a href="/index/Se#semigroups">Index entries for sequences related to semigroups</a> %e A058170 1; 2,1; 3,7,2; 10,28,33,7; 82,153,261,213,37; ... %Y A058170 Row sums give A058107. %K A058170 nonn,tabl,hard %O A058170 1,2 %A A058170 _Christian G. Bower_, Nov 19 2000