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Search: id:A053529
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| A053529 |
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n! * number of partitions of n. |
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+0
7
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| 1, 1, 4, 18, 120, 840, 7920, 75600, 887040, 10886400, 152409600, 2235340800, 36883123200, 628929100800, 11769069312000, 230150688768000, 4833164464128000, 105639166144512000, 2464913876705280000, 59606099200327680000, 1525429559126753280000
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Commuting permutations: number of ordered pairs g, h in Symm(n) such that gh = hg.
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REFERENCES
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R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 5.12, solution.
R. P. Stanley, Pairs with equal squares, Problem 10654, Amer. Math. Monthly, 107 (April 2000), solution p. 368.
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MAPLE
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seq(count(Permutation(n))*count(Partition(n)), n=1..20); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 16 2006
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CROSSREFS
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Cf. A000041, A072169, A079860.
Sequence in context: A141714 A137567 A162224 this_sequence A005442 A084661 A112294
Adjacent sequences: A053526 A053527 A053528 this_sequence A053530 A053531 A053532
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KEYWORD
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nonn,easy,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Jan 16 2000
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