A256036 - OEIS

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A256036

Triangle read by rows: number of idempotents of rank k in Brauer monoid B_n.

1, 0, 1, 1, 0, 1, 0, 9, 0, 1, 9, 0, 30, 0, 1, 0, 225, 0, 70, 0, 1, 225, 0, 1575, 0, 135, 0, 1, 0, 11025, 0, 6615, 0, 231, 0, 1, 11025, 0, 132300, 0, 20790, 0, 364, 0, 1, 0, 893025, 0, 873180, 0, 54054, 0, 540, 0, 1, 893025, 0, 16372125, 0, 4054050, 0, 122850, 0, 765, 0, 1

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OFFSET

0,8

LINKS

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

I. Dolinka, J. East, A. Evangelou, D. FitzGerald, N. Ham, et al., Enumeration of idempotents in diagram semigroups and algebras, arXiv preprint arXiv:1408.2021 [math.GR], 2014.

EXAMPLE

Triangle begins:

0, 1

1, 0, 1

0, 9, 0, 1

9, 0, 30, 0, 1

0, 225, 0, 70, 0, 1

225, 0, 1575, 0, 135, 0, 1

0, 11025, 0, 6615, 0, 231, 0, 1

11025, 0, 132300, 0, 20790, 0, 364, 0, 1

0, 893025, 0, 873180, 0, 54054, 0, 540, 0, 1

893025, 0, 16372125, 0, 4054050, 0, 122850, 0, 765, 0, 1

...

CROSSREFS

Sequence in context: A118811 A200488 A249418 * A065471 A310000 A199284

Adjacent sequences: A256033 A256034 A256035 * A256037 A256038 A256039

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Mar 14 2015

STATUS

approved