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 1-4 of 4 results.

A057992 Number of commutative quasigroups of order n.

Original entry on oeis.org

1, 1, 1, 3, 7, 11, 491, 6381, 10940111, 1225586965, 130025302505741, 252282619993126717, 2209617218725712597768722, 98758655816833782283724345637
Offset: 0

Views

Author

Christian G. Bower, Nov 01 2000

Keywords

Links

Crossrefs

Cf. A057991-A057994, A057771, A057996, A035481, A350009, A350010.

Extensions

Added a(7) = 6381, W. Edwin Clark, Jan 04 2011
a(8)-a(13) from Ian Wanless, Dec 08 2021

A089925 Number of commutative loops (quasigroups with an identity element) of order n.

Original entry on oeis.org

0, 1, 1, 1, 2, 1, 8, 17, 2265, 30583, 358335026, 69522550106, 55355570223093935, 206176045800229002160
Offset: 0

Views

Author

Christian G. Bower and Juergen Buntrock (jubu(AT)jubu.com), Nov 14 2003

Keywords

Links

Crossrefs

Cf. A057771, A035481, A350009, A350010, A057992.

Extensions

a(9) from Michael Thwaites (michael.thwaites(AT)ucop.edu), Jan 23 2004
a(0) prepended by Jianing Song, Oct 26 2019
a(10)-a(13) from Ian Wanless, Dec 08 2021

A350010 a(n) is the number of equivalence classes of symmetric Latin squares of order n.

Original entry on oeis.org

1, 1, 1, 2, 1, 6, 7, 423, 3460, 35878510, 6320290037, 4612966007179768, 15859695832489637513
Offset: 1

Views

Author

Ian Wanless, Dec 08 2021

Keywords

Comments

Equivalence here includes permutation of the symbols as well as simultaneously applying one permutation to both the rows and columns.

Links

Crossrefs

The odd terms agree with A350009. Cf. A035481.

A350017 Number of isotopism classes containing symmetric unipotent reduced Latin squares of order 2n.

Original entry on oeis.org

1, 1, 1, 6, 396, 526915616, 1132835421602062347
Offset: 1

Views

Author

Ian Wanless, Dec 08 2021

Keywords

Comments

Isotopism classes are obtained by permuting rows, permuting columns and permuting symbols. There is a stronger notion of equivalence called "species" (also known as main classes and paratopism classes). For this particular problem the counts for species equal the counts for isotopism classes.

Links

Crossrefs

For odd n the terms equal A000474.
Cf. A350009.
Showing 1-4 of 4 results.

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

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