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A256039 Triangle read by rows: number of idempotents of rank k in partial Brauer monoid PB_n. 0
1, 1, 1, 4, 2, 1, 16, 18, 3, 1, 100, 88, 48, 4, 1, 676, 860, 280, 100, 5, 1, 5776, 6696, 4020, 680, 180, 6, 1, 53824, 76552, 35196, 13580, 1400, 294, 7, 1, 583696, 805568, 531328, 131936, 37240, 2576, 448, 8, 1, 6864400, 10765008, 6159168, 2571744, 397656, 88200, 4368, 648, 9, 1, 90174016, 141145120, 101644560, 32404800, 9780960, 1027152, 187320, 6960, 900, 10, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
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:
1,
1, 1,
4, 2, 1,
16, 18, 3, 1,
100, 88, 48, 4, 1,
676, 860, 280, 100, 5, 1,
5776, 6696, 4020, 680, 180, 6, 1,
53824, 76552, 35196, 13580, 1400, 294, 7, 1,
583696, 805568, 531328, 131936, 37240, 2576, 448, 8, 1,
6864400, 10765008, 6159168, 2571744, 397656, 88200, 4368, 648, 9, 1,
90174016, 141145120, 101644560, 32404800, 9780960, 1027152, 187320, 6960, 900, 10, 1,
...
CROSSREFS
Sequence in context: A236830 A269736 A264535 * A152391 A144088 A039948
KEYWORD
nonn,tabl
AUTHOR
N. J. A. Sloane, Mar 14 2015
STATUS
approved

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Last modified March 1 06:15 EST 2024. Contains 370430 sequences. (Running on oeis4.)