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.

Previous Showing 11-16 of 16 results.

A030260 Number of nonisomorphic commutative groupoids with no idempotents.

Original entry on oeis.org

1, 0, 1, 38, 13872, 83360520, 10203847031340, 31023254154131753920, 2765562268014305034000397632, 8332535835277886736134596954072281240, 960864308045670310058158724983067048253497223280
Offset: 0

Views

Author

Christian G. Bower, Feb 15 1998 and May 15 1998

Keywords

Links

Crossrefs

Cf. A001329, A001425, A038021.

A038023 Triangle: T(n,k), k<=n: commutative groupoids with a nontrivial symmetry with n elements and k idempotents.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 3, 6, 0, 4, 96, 214, 128, 64, 38, 54248, 83925, 54223, 28254, 10223, 1894
Offset: 0

Views

Author

Christian G. Bower, May 15 1998

Keywords

Links

Crossrefs

Cf. A001329, A001425, A030259, A030262, A030265.

Formula

Difference of A038021 and A038022.

A038016 Number of pointed (distinguished element) commutative groupoids.

Original entry on oeis.org

1, 8, 369, 175296, 1271911125, 182810647581408, 638870563764553089382, 64388603066507462072885127552, 216467350495255331602790475962162008809, 27557319224243445068662283861406911750848082900080
Offset: 1

Views

Author

Christian G. Bower, May 15 1998

Keywords

Links

Crossrefs

Cf. A001329, A001425.

A038022 Triangle: T(n,k), k<=n: commutative groupoids with no symmetry with n elements and k idempotents.

Original entry on oeis.org

1, 0, 1, 1, 2, 1, 35, 51, 27, 3, 13776, 18330, 9152, 2016, 164, 83306272, 104124850, 52056277, 13006746, 1622527, 80461
Offset: 0

Views

Author

Christian G. Bower, May 15 1998

Keywords

Links

Crossrefs

Cf. A001329, A001425, A030258, A030261, A030264.

A030256 Number of nonisomorphic commutative groupoids with a nontrivial symmetry.

Original entry on oeis.org

0, 0, 0, 13, 540, 232767
Offset: 0

Views

Author

Christian G. Bower

Keywords

Links

Crossrefs

A001425 - A030255.

A118542 Number of nonisomorphic groupoids with <= n elements.

Original entry on oeis.org

1, 2, 12, 3342, 178985294, 2483527716080119, 14325590005802419238355799, 50976900301828909677297289506452525838, 155682086691137998248942804080553139214788341933547854
Offset: 0

Views

Author

Jonathan Vos Post, May 06 2006

Keywords

Comments

The number of isomorphism classes of closed binary operations on sets of order <= n. See formulas by Christian G. Bower in A001329 Number of nonisomorphic groupoids with n elements.

Examples

			a(5) = 1 + 1 + 10 + 3330 + 178981952 + 2483527537094825 = 2483527716080119 is prime.

Crossrefs

Cf. A001424, A001425, A002489, A006448, A029850, A030245-A030265, A030271, A038015-A038023.

Formula

a(n) = SUM[i=0..n] A001329(i). a(n) = SUM[i=0..n] (A079173(i)+A027851(i)). a(n) = SUM[i=0..n] (A079177(i)+A079180(i)). a(n) = SUM[i=0..n] (A079183(i)+A001425(i)). a(n) = SUM[i=0..n] (A079187(i)+A079190(i)). a(n) = SUM[i=0..n] (A079193(i)+A079196(i)+A079199(i)+A001426(i)).
Previous Showing 11-16 of 16 results.

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

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