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Search: id:A151338
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| A151338 |
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Triangle read by rows: T(n,k) = number of partitions of [1..k] into n nonempty clumps of sizes 1, 2, 3, 4 or 5 (n >= 0, 0 <= k <= 5n). |
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+0
4
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| 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 3, 7, 15, 31, 56, 91, 126, 126, 0, 0, 0, 1, 6, 25, 90, 301, 938, 2737, 7455, 18711, 41811, 81081, 126126, 126126, 0, 0, 0, 0, 1, 10, 65, 350, 1701, 7686, 32725, 132055, 505351, 1824823, 6173167, 19339320, 55096041
(list; graph; listen)
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OFFSET
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0,11
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COMMENT
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Row n has 5n+1 entries.
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LINKS
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David Applegate and N. J. A. Sloane, The Gift Exchange Problem (arXiv:0907.0513, 2009)
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EXAMPLE
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The triangle begins:
1
0, 1, 1, 1, 1, 1
0, 0, 1, 3, 7, 15, 31, 56, 91, 126, 126
0, 0, 0, 1, 6, 25, 90, 301, 938, 2737, 7455, 18711, 41811, 81081, 126126, 126126
0, 0, 0, 0, 1, 10, 65, 350, 1701, 7686, 32725, 132055, 505351, 1824823, 6173167, 19339320, 55096041, 138654516, 295891596, 488864376, 488864376
0, 0, 0, 0, 0, 1, 15, 140, 1050, 6951, 42315, 241780, 1310925, 6782776, 33549516, 158533375, 713733020, 3046944901, 12246267033, 45892143297, 158167994985, 491492022021, 1336310771796, 3030225834636, 5194672859376, 5194672859376
...
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CROSSREFS
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This is one of a sequence of triangles: A144331, A144385, A144643, A151338, A151359, ...
See A151509, A151510 for other versions.
Sequence in context: A098583 A043729 A137170 this_sequence A023424 A006778 A007574
Adjacent sequences: A151335 A151336 A151337 this_sequence A151339 A151340 A151341
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KEYWORD
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nonn,tabf
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), May 13 2009
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