%I #17 Feb 06 2021 15:20:40
%S 0,2,50,2352,153002,15876046,7676692858
%N Number of associative non-commutative closed binary operations on a set of order n.
%C a(n) + A079192(n) + A079195(n) + A023815(n) = A002489(n).
%C Each a(n) is equal to the sum of the products of each element in row n of A079200 and the corresponding element of A079210.
%C Since this is the number of labeled noncommutative semigroups on an n-set, a(n) = A023814(n)-A023815(n). - _Stanislav Sykora_, Apr 03 2016
%H C. van den Bosch, <a href="http://cosmos.ucc.ie/~cjvdb1/html/binops.shtml">Closed binary operations on small sets</a>
%H <a href="/index/Se#semigroups">Index entries for sequences related to semigroups</a>
%Y Cf. A023814, A023815, A079192, A079195, A079199, A079200.
%K nonn,more
%O 1,2
%A Christian van den Bosch (cjb(AT)cjb.ie), Jan 03 2003
%E a(5)-a(7) added by _Stanislav Sykora_, Apr 03 2016