cp's OEIS Frontend

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.

Showing 1-3 of 3 results.

A079178 Number of isomorphism classes of non-anti-associative closed binary operations on a set of order n, listed by class size.

Original entry on oeis.org

0, 2, 6, 3, 10, 78, 3229, 2, 1, 12, 30, 246, 495, 48427, 178914959
Offset: 1

Views

Author

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

Keywords

Comments

A079178(n)+A079181(n)=A079171(n).
Elements per row: 1,2,4,8,16,30,... (given by A027423, number of positive divisors of n!)
First four rows: 0; 2,6; 3,10,78,3229; 2,1,12,30,246,495,48427,178914959
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.
The sum of each row x of this sequence is given by A079177(x).

Links

Crossrefs

Cf. A079176, A079177, A079179.

A079180 Number of isomorphism classes of anti-associative closed binary operations on a set of order n.

Original entry on oeis.org

1, 0, 2, 10, 17780
Offset: 0

Views

Author

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

Keywords

Links

Crossrefs

Row sums of A079181.
Cf. A001329, A079177, A079179 (labeled case).

Formula

a(n) = A001329(n) - A079177(n).

Extensions

a(0)=1 prepended and a(1) corrected by Kamil Zabielski, Aug 28 2024

A079179 Number of anti-associative closed binary operations on a set of order n.

Original entry on oeis.org

1, 0, 2, 52, 421560
Offset: 0

Views

Author

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

Keywords

Links

Crossrefs

Cf. A079176, A079180 (isomorphism classes), A079181, A079210.

Formula

a(n) = A002489(n) - A079176(n).
a(n) = Sum_{k>=1} A079181(n,k)*A079210(n,k).

Extensions

a(0)=1 prepended and a(1) corrected by Kamil Zabielski, Aug 28 2024
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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