A289620 - OEIS

A289620

Triangle read by rows: T(n,r), 0 <= r <= n, is the number of idempotents of rank r in the twisted planar partition monoid PP_n^tau.

1, 0, 1, 0, 5, 1, 0, 33, 10, 1, 0, 253, 93, 15, 1, 0, 2147, 880, 178, 20, 1, 0, 19593, 8599, 1982, 288, 25, 1, 0, 188837, 86762, 21723, 3684, 423, 30, 1, 0, 1899107, 900997, 238419, 44767, 6111, 583, 35, 1, 0, 19761209, 9595264, 2638114, 531656, 81606, 9388, 768, 40, 1, 0, 211447863, 104447385, 29503900, 6255952, 1044248, 136740, 13640, 978, 45, 1

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OFFSET

0,5

COMMENTS

Values were computed using the Semigroups package for GAP.

LINKS

Table of n, a(n) for n=0..65.

Igor Dolinka, James East, Athanasios Evangelou, Desmond FitzGerald, Nicholas Ham, James Hyde, Nicholas Loughlin, Idempotent Statistics of the Motzkin and Jones Monoids, arXiv:1507.04838 [math.CO], 2015-2016.

CROSSREFS

Cf. A281441, A281442, A286867 (row sums).

Sequence in context: A361550 A123260 A019113 * A019107 A019183 A019156

Adjacent sequences: A289617 A289618 A289619 * A289621 A289622 A289623

KEYWORD

nonn,tabl

AUTHOR

James East, Oct 05 2017

STATUS

approved