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 A058118 #8 Mar 31 2012 10:23:58 %S A058118 1,2,1,5,5,2,18,24,16,6,93,123,112,58,19,930,754,764,542,254,68,22899, %T A058118 6721,5567,4751,2933,1214,285,1937266,123988,49969,41939,31392,17396, %U A058118 6513,1376,613365656,8265721,739317,410158,328937,223226,113160,38979,7510 %N A058118 Triangle: self-converse semigroups of order n with k idempotents. %H A058118 Andreas Distler, <a href="http://hdl.handle.net/10023/945">Classification and Enumeration of Finite Semigroups</a>, A Thesis Submitted for the Degree of PhD, University of St Andrews (2010). %H A058118 <a href="/index/Se#semigroups">Index entries for sequences related to semigroups</a> %e A058118 1; 2,1; 5,5,2; 18,24,16,6; 93,123,112,58,19; ... %Y A058118 Row sums give A029851. Main diagonal: A058122. Columns 1-3: A058119-A058121. %K A058118 nonn,tabl,hard %O A058118 1,2 %A A058118 _Christian G. Bower_, Nov 10 2000 %E A058118 More terms from _Andreas Distler_, Jan 13 2011