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 A079174 #6 Jul 10 2011 18:42:30 %S A079174 0,2,3,1,12,71,3222,0,1,14,23,270,495,48748,178932213 %N A079174 Number of isomorphism classes of non-associative closed binary operations on a set of order n, listed by class size. %C A079174 A079174(n)+A079175(n)=A079171(n) %C A079174 Elements per row: 1,2,4,8,16,30,60,96 (A027423, number of positive divisors of n!) %C A079174 First four rows: 0; 2,3; 1,12,71,3222; 0,1,14,23,270,495,48748,178932213 %C A079174 The sum of each row n is given by A079173(n). %H A079174 C. van den Bosch, <a href="http://cosmos.ucc.ie/~cjvdb1/html/binops.shtml">Closed binary operations on small sets</a> %H A079174 <a href="/index/Gre#groupoids">Index entries for sequences related to groupoids</a> %Y A079174 Cf. A079172, A079173, A079175. %K A079174 nonn,tabf %O A079174 1,2 %A A079174 Christian van den Bosch (cjb(AT)cjb.ie), Jan 03 2003