A351730 Number of labeled idempotent semigroups of order n.

1, 1, 4, 35, 604, 16727, 681232, 38187291, 2810370122, 261999605819

Offset

0,3

Comments

a(n) is also the number of labeled idempotent monoids of order n+1 with a fixed identity.

Links

Table of n, a(n) for n=0..9.

Crossrefs

Main diagonal of A058166 and A058158.

Cf. A023814, A058112 (isomorphism classes), A351731.

Sequence in context: A238390 A251591 A346802 * A125798 A129581 A371633

Adjacent sequences: A351727 A351728 A351729 * A351731 A351732 A351733

Keyword

nonn,hard,more

Author

Andrew Howroyd, Feb 17 2022

Status

approved