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.

User: Steve Szabo

Steve Szabo's wiki page.

Steve Szabo has authored 3 sequences.

A320420 Number of monoids of order n that are not groups.

Original entry on oeis.org

0, 0, 1, 6, 33, 227, 2235, 31558, 1668992
Offset: 0

Author

Steve Szabo, Jan 07 2019

Keywords

Crossrefs

Formula

a(n) = A058129(n) - A000001(n).

A318986 Number of loops of order n that are not groups.

Original entry on oeis.org

0, 0, 0, 0, 0, 5, 107, 23745, 106228844, 9365022303538, 20890436195945769615, 1478157455158044452849321015
Offset: 0

Author

Steve Szabo, Sep 06 2018

Keywords

Comments

A loop is a quasigroup with an identity element. - Muniru A Asiru, Dec 13 2018

Crossrefs

Formula

a(n) = A057771(n) - A000001(n).

Extensions

a(7)-a(11) from Muniru A Asiru, Dec 07 2018
a(0) prepended by Jianing Song, Oct 26 2019

A318987 Number of semigroups of order n without identity.

Original entry on oeis.org

1, 0, 3, 17, 153, 1687, 26397, 1596113, 3682361420
Offset: 0

Author

Steve Szabo, Sep 06 2018

Keywords

Crossrefs

Formula

a(n) = A027851(n) - A058129(n).

Extensions

More terms from Joerg Arndt, Dec 09 2018
a(0) prepended by Jianing Song, Oct 26 2019