A090599 Number of n-element labeled commutative groupoids with an identity.

1, 4, 81, 16384, 48828125, 2821109907456, 3909821048582988049, 154742504910672534362390528, 202755595904452569706561330872953769, 10000000000000000000000000000000000000000000000

Offset

1,2

Comments

Also labeled commutative groupoids with an absorbant (zero) element.

Links

Table of n, a(n) for n=1..10.

Eric Postpischil Posting to sci.math newsgroup, May 21 1990

Eric Weisstein's World of Mathematics, Groupoid.

Index entries for sequences related to groupoids

Formula

a(n) = n^(1+binomial(n, 2))

Crossrefs

a(n) = A076113(n)*n. Cf. A038017.

Sequence in context: A068087 A324088 A357513 * A133396 A233001 A357781

Adjacent sequences: A090596 A090597 A090598 * A090600 A090601 A090602

Keyword

nonn

Author

Christian G. Bower, Dec 05 2003

Status

approved