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Number of isomorphism classes of non-associative closed binary operations on a set of order n.
9

%I #7 Mar 30 2012 17:37:12

%S 0,5,3306,178981764,2483527537092910,14325590003318891522247046,

%T 50976900301814584087291487087212542367

%N Number of isomorphism classes of non-associative closed binary operations on a set of order n.

%C A027851(n)+A079173(n)=A001329(n)

%C Each a(n) is equal to the sum of the elements in row n of A079174.

%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. A027851, A079172, A079174.

%K nonn

%O 1,2

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

%E More terms from _Christian G. Bower_, Nov 26 2003