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 1-2 of 2 results.

A090602 Number of n-element labeled groupoids with an identity.

Original entry on oeis.org

0, 1, 4, 243, 1048576, 762939453125, 170581728179578208256, 18562115921017574302453163671207, 1427247692705959881058285969449495136382746624, 106111661199647248543687855752712667991103904330482569981872649
Offset: 0

Views

Author

Christian G. Bower, Dec 05 2003

Keywords

Comments

Also labeled groupoids with an absorbant (zero) element.

Links

Crossrefs

Cf. A090601 (isomorphism classes), A090603.

Programs

Formula

a(n) = n^((n-1)^2+1).
a(n) = A090603(n)*n.

Extensions

a(0)=0 prepended and a(9) added by Andrew Howroyd, Jan 23 2022

A090600 Number of n-element groupoids with an identity, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).

Original entry on oeis.org

1, 2, 30, 22456, 3179460875, 118459556737869096, 1841479754519556293280702095, 17699004125822025124951660289473617122688, 146207646053305863964379580591072585873215024249550168360
Offset: 1

Views

Author

Christian G. Bower, Dec 05 2003

Keywords

Comments

Also partial groupoids with n-1 elements or groupoids with an absorbant (zero) element with n elements in each case the same equivalence.

Links

Formula

a(n) = (A090601(n) + A090604(n))/2
Showing 1-2 of 2 results.

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

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