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Search: id:A060523
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| A060523 |
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Triangle T(n,k) = number of degree-n permutations with k even cycles, k=0..n. |
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+0
3
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| 1, 1, 0, 1, 1, 0, 3, 3, 0, 0, 9, 12, 3, 0, 0, 45, 60, 15, 0, 0, 0, 225, 345, 135, 15, 0, 0, 0, 1575, 2415, 945, 105, 0, 0, 0, 0, 11025, 18480, 9030, 1680, 105, 0, 0, 0, 0, 99225, 166320, 81270, 15120, 945, 0, 0, 0, 0, 0, 893025, 1596105, 897750, 217350, 23625
(list; table; graph; listen)
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OFFSET
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0,7
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REFERENCES
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I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983, p. 189, Exercise 3.3.13.
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FORMULA
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E.g.f.: (1+x)^((1-y)/2)/(1-x)^((1+y)/2).
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EXAMPLE
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[1], [1, 0], [1, 1, 0], [3, 3, 0, 0], [9, 12, 3, 0, 0], [45, 60, 15, 0, 0, 0], [225, 345, 135, 15, 0, 0, 0], [1575, 2415, 945, 105, 0, 0, 0, 0], [11025, 18480, 9030, 1680, 105, 0, 0, 0, 0], [99225, 166320, 81270, 15120, 945, 0, 0, 0, 0, 0], [893025, 1596105, 897750, 217350, 23625, 945, 0, 0, 0, 0, 0], ...
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CROSSREFS
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Cf. A060524.
Sequence in context: A152893 A129533 A155999 this_sequence A163535 A102752 A104548
Adjacent sequences: A060520 A060521 A060522 this_sequence A060524 A060525 A060526
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 01 2001
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