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 A079181 #16 Aug 28 2024 16:37:11
%S A079181 1,0,2,0,0,2,0,8,0,0,2,0,29,0,383,17366
%N A079181 Number of isomorphism classes of anti-associative closed binary operations on a set of order n, listed by class size.
%C A079181 Elements per row: 1,1,2,4,8,16,30,... (given by A027423, number of positive divisors of n!)
%H A079181 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 A079181 <a href="/index/Gre#groupoids">Index entries for sequences related to groupoids</a>
%F A079181 T(n,k) = A079171(n,k) - A079178(n,k).
%F A079181 A079179(n) = Sum_{k>=1} A079210(n,k) * T(n,k).
%e A079181 First rows:
%e A079181 1;
%e A079181 0;
%e A079181 2,0;
%e A079181 0,2,0,8;
%e A079181 0,0,2,0,29,0,383,17366;
%e A079181 ...
%Y A079181 Cf. A027423 (row lengths), A079176, A079177, A079180 (row sums).
%K A079181 nonn,tabf,more
%O A079181 0,3
%A A079181 Christian van den Bosch (cjb(AT)cjb.ie), Jan 03 2003
%E A079181 a(0)=1 prepended and a(1) corrected by _Kamil Zabielski_, Aug 28 2024