The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A090657 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A090657

Triangle read by rows: T(n,k) = number of functions from [1,2,...,n] to [1,2,...,n] such that the image contains exactly k elements (0<=k<=n).
(history; published version)

#51 by Alois P. Heinz at Sun Jan 02 18:29:10 EST 2022

STATUS

editing

approved

#50 by Alois P. Heinz at Sun Jan 02 18:29:07 EST 2022

EXAMPLE

1;

0, 1;

0, 2, 2;

0, 3, 18, 6;

0, 4, 84, 144, 24;

...

STATUS

approved

editing

#49 by Alois P. Heinz at Wed Jun 07 19:49:40 EDT 2017

STATUS

editing

approved

#48 by Alois P. Heinz at Wed Jun 07 19:31:42 EDT 2017

FORMULA

T(2n,n) = A288312(n). - Alois P. Heinz, Jun 07 2017

CROSSREFS

Cf. A101817, A288312.

STATUS

approved

editing

#47 by R. J. Mathar at Fri Jun 17 05:15:50 EDT 2016

STATUS

editing

approved

#46 by R. J. Mathar at Fri Jun 17 05:15:45 EDT 2016

REFERENCES

C. M. Ringel, The Catalan combinatorics of the hereditary artin algebras, arXiv preprint arXiv:1502.06553, 2015

LINKS

C. M. Ringel, <a href="http://arxiv.org/abs/1502.06553">The Catalan combinatorics of the hereditary artin algebras</a>, arXiv preprint arXiv:1502.06553, 2015

STATUS

approved

editing

#45 by N. J. A. Sloane at Wed Nov 11 15:19:07 EST 2015

STATUS

editing

approved

#44 by N. J. A. Sloane at Wed Nov 11 15:19:04 EST 2015

REFERENCES

C. M. Ringel, The Catalan combinatorics of the hereditary artin algebras, arXiv preprint arXiv:1502.06553, 2015

STATUS

approved

editing

#43 by Alois P. Heinz at Wed May 06 16:46:51 EDT 2015

STATUS

editing

approved

#42 by Alois P. Heinz at Wed May 06 16:46:47 EDT 2015

MAPLE

seq (seq (T(n, k), k=0..n), n=0..10);

STATUS

approved

editing