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 A234843 #8 Dec 31 2013 12:36:03 %S A234843 1,2,5,16,51,201,877,4443,25284,161698,1145508,8910291,75373563, %T A234843 687950735,6727985390 %N A234843 Number of commutative inverse semigroups of order n. %H A234843 Martin E. Malandro, <a href="http://arxiv.org/abs/1312.7192">Enumeration of finite inverse semigroups</a>, arXiv:1312.7192 [math.CO] %Y A234843 Cf. A001428 (inverse semigroups), A234844 (inverse monoids), A234845 (commutative inverse monoids). %K A234843 nonn,hard,more %O A234843 1,2 %A A234843 _Joerg Arndt_, Dec 31 2013