A289713 The order of the semigroup of orientation-preserving partial transformations on n elements.

1, 2, 9, 61, 449, 3161, 21145, 136529, 862209, 5369617, 33133481, 203119577, 1239049729, 7528608985, 45596026169, 275385806881, 1659295498241, 9977108934689, 59881303252297, 358815987469673, 2146943650081281, 12829239786138217, 76571416493573849, 456525052642949681

Offset

0,2

Comments

Row sums of A289710 and of A289711.

Links

Table of n, a(n) for n=0..23.

A. Umar, Combinatorial Results for Semigroups of Orientation-Preserving Partial Transformations, J. Int. Seq. 14 (2011) # 11.7.5, Tables 2.1, 2.2 and 2.3.

Crossrefs

Cf. A289710, A289711.

Sequence in context: A269600 A269460 A207649 * A341956 A349289 A053983

Adjacent sequences: A289710 A289711 A289712 * A289714 A289715 A289716

Keyword

nonn,easy

Author

R. J. Mathar, Sep 02 2017

Status

approved