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A088994
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Number of permutations in the symmetric group S_n such that the size of their centralizer is odd.
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3
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1, 0, 2, 8, 24, 144, 720, 8448, 64512, 576000, 5529600, 74972160, 887546880, 11285084160, 168318259200, 2843121254400, 44790578380800, 747955947110400, 13937735643955200, 287117441217331200, 5838778006909747200
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OFFSET
| 1,3
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FORMULA
| E.g.f.: Product_{m >= 1} (1+x^(2*m-1)/(2*m-1)). - Vladeta Jovovic (vladeta(AT)eunet.rs), Nov 05 2003
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PROG
| (PARI) {a(n)=if(n<1, 0, n!*polcoeff( prod(k=1, n, 1+(k%2)*x^k/k, 1+x*O(x^n)), n))} /* Michael Somos Sep 19 2006 */
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CROSSREFS
| Sequence in context: A176475 A145238 A093458 * A141598 A071599 A047695
Adjacent sequences: A088991 A088992 A088993 * A088995 A088996 A088997
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KEYWORD
| nonn
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AUTHOR
| Yuval Dekel (dekelyuval(AT)hotmail.com), Nov 01 2003
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EXTENSIONS
| More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Nov 03 2003
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