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 A079199 #10 Apr 03 2016 20:19:48 %S A079199 0,2,12,130,1590,26491,1610381,3683808612,105978166390449 %N A079199 Number of isomorphism classes of associative non-commutative closed binary operations on a set of order n. %C A079199 A079193(n)+A079196(n)+A079199(n)+A001426(n)=A001329(n). %C A079199 Each a(n) is equal to the sum of the elements in row n of A079200. %C A079199 Since this is the number of nonisomorphic noncommutative semigroups of order n, A079199(n)=A027851(n)-A001426(n). - _Stanislav Sykora_, Apr 03 2016 %H A079199 C. van den Bosch, <a href="http://cosmos.ucc.ie/~cjvdb1/html/binops.shtml">Closed binary operations on small sets</a> %H A079199 <a href="/index/Se#semigroups">Index entries for sequences related to semigroups</a> %Y A079199 Cf. A001426, A027851, A079193, A079196, A079198, A079200. %K A079199 nonn %O A079199 1,2 %A A079199 Christian van den Bosch (cjb(AT)cjb.ie), Jan 03 2003 %E A079199 Added terms a(5)-a(9). - _Stanislav Sykora_, Apr 03 2016