%I #21 Sep 22 2024 18:39:13
%S 1,0,2,10,17780
%N Number of isomorphism classes of anti-associative closed binary operations on a set of order n.
%H Christian van den Bosch, <a href="https://web.archive.org/web/20071014230143/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>
%H <a href="/index/Gre#groupoids">Index entries for sequences related to groupoids</a>
%F a(n) = A001329(n) - A079177(n).
%Y Row sums of A079181.
%Y Cf. A001329, A079177, A079179 (labeled case).
%K nonn
%O 0,3
%A Christian van den Bosch (cjb(AT)cjb.ie), Jan 03 2003
%E a(0)=1 prepended and a(1) corrected by _Kamil Zabielski_, Aug 28 2024