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Search: id:A147679
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| A147679 |
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Triangle read by rows: T(n,k) (n >= 1, 0 <= k <= n-1) is the number of permutations of [1..n] of spread k. |
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+0
1
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| 1, 1, 1, 0, 3, 3, 4, 8, 4, 8, 20, 25, 25, 25, 25, 144, 108, 108, 144, 108, 108
(list; table; graph; listen)
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OFFSET
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1,5
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COMMENT
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The reference gives more terms, formulae, connection with A003112, etc.
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LINKS
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R. L. GRAHAM and D. H. LEHMER, ON THE PERMANENT OF SCHUR'S MATRIX, J. Australian Math. Soc., 21A (1976), 487-497.
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EXAMPLE
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Triangle begins:
1,
1, 1,
0, 3, 3,
4, 8, 4, 8
20, 25, 25, 25, 25,
144, 108, 108, 144, 108, 108,
...
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CROSSREFS
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Cf. A003112.
Row sums: A000142.
Sequence in context: A087329 A011959 A049927 this_sequence A137417 A137418 A155822
Adjacent sequences: A147676 A147677 A147678 this_sequence A147680 A147681 A147682
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KEYWORD
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nonn,tabl,more
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), May 01 2009
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