A084965 Number of labeled totally ordered semigroups with n elements.

1, 1, 6, 44, 386, 3852, 42640, 516791, 6817378, 98091071, 1569786228

Offset

0,3

Links

Table of n, a(n) for n=0..10.

Petr Gajdoš and Martin Kuřil, Ordered semigroups of size at most 7 and linearly ordered semigroups of size at most 10, Semigroup Forum, 89 (2014), 639-663.

J. Slaney, FINDER: Finite Domain Enumerator

Crossrefs

Cf. A023814.

Sequence in context: A090442 A286867 A361649 * A203159 A279085 A124996

Adjacent sequences: A084962 A084963 A084964 * A084966 A084967 A084968

Keyword

nonn,hard,more

Author

Michael Somos, Jun 15 2003

Extensions

a(9)-a(10) from Gajdoš and Kuřil added by Andrey Zabolotskiy, Mar 24 2021

Status

approved