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Number of isomorphism classes of non-anti-commutative closed binary operations on a set of order n, listed by class size.
4

%I #6 Jul 10 2011 18:42:30

%S 0,0,4,1,4,44,2285,0,0,0,24,64,212,35240,147088764

%N Number of isomorphism classes of non-anti-commutative closed binary operations on a set of order n, listed by class size.

%C A079188(n)+A079191(n)=A079171(n).

%C Elements per row: 1,2,4,8,16,30,... (given by A027423, number of positive divisors of n!)

%C First four rows: 0; 0,4; 1,4,44,2285; 0,0,0,24,64,212,35240,147088764

%C A079176(x) is equal to the sum of the products of each element in row x of this sequence and the corresponding element of A079210.

%C The sum of each row x of this sequence is given by A079177(x).

%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/Gre#groupoids">Index entries for sequences related to groupoids</a>

%Y Cf. A079186, A079187, A079191.

%K nonn,tabf

%O 1,3

%A Christian van den Bosch (cjb(AT)cjb.ie), Jan 03 2003