The On-Line Encyclopedia of Integer Sequences (OEIS)

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Number of isomorphism classes of associative commutative non-anti-associative non-anti-commutative closed binary operations on a set of order n.
(history; published version)

#6 by Russ Cox at Sun Jul 10 18:22:18 EDT 2011

LINKS

<a href="/Sindx_index/Se.html#semigroups">Index entries for sequences related to semigroups</a>

Discussion

Sun Jul 10

18:22

OEIS Server: https://oeis.org/edit/global/81

#5 by N. J. A. Sloane at Thu Nov 11 07:34:06 EST 2010

LINKS

<a href="/Sindx_Se.html#semigroups">Index entries for sequences related to semigroups</a>

KEYWORD

nonn,new

nonn

#4 by N. J. A. Sloane at Fri Feb 27 03:00:00 EST 2009

LINKS

<a href="http://www.research.att.com/~njas/sequences/Sindx_Se.html#semigroups">Index entries for sequences related to semigroups</a>

KEYWORD

nonn,new

nonn

#3 by N. J. A. Sloane at Tue Jan 24 03:00:00 EST 2006

KEYWORD

nonn,new

nonn

AUTHOR

Christian van den Bosch (cjvdb1cjb(AT)student.cs.ucccjb.ie), Jan 03 2003

#2 by N. J. A. Sloane at Thu Feb 19 03:00:00 EST 2004

NAME

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

LINKS

<a href="http://www.research.att.com/~njas/sequences/Sindx_Se.html#semigroups">Index entries for sequences related to semigroups</a>

KEYWORD

nonn,new

nonn

#1 by N. J. A. Sloane at Fri May 16 03:00:00 EDT 2003

NAME

Number of isomorphic classes of associative commutative non-anti-associative non-anti-commutative closed binary operations on a set of order n.

DATA

0, 3, 12, 58

OFFSET

1,2

COMMENTS

A079231(n)+A079233(n)+A079235(n)+A079237(n)+A079196(n)+A079241(n)+A079243(n)+A079245(n)+A063524(n)=A002489(n)

Each a(n) is equal to the sum of the elements in row n of A079209.

CROSSREFS

Cf. A079209, A079244, A079231, A079233, A079235, A079237, A079196, A079241, A079243, A063524.

KEYWORD

nonn

AUTHOR

Christian van den Bosch (cjvdb1(AT)student.cs.ucc.ie), Jan 03 2003

STATUS

approved