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Search: id:A129255
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| A129255 |
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Rencontres numbers: permutations with exactly 12 fixed points. |
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+0
1
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| 1, 0, 91, 910, 16380, 272272, 4919460, 93419352, 1868513010, 39238479280, 863247190806, 19854684036460, 476512419579196, 11912810484279600, 309733072600927300, 8362792960207653240, 234158202885844712475
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OFFSET
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0,3
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FORMULA
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G.f.:exp(-x)/(1-x)*(x^12/12!) . [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 03 2009]
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MAPLE
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a:=n->sum(n!*sum((-1)^k/(k-11)!, j=0..n), k=11..n): seq(-a(n)/12!, n=11..28);
restart: G(x):=exp(-x)/(1-x)*(x^12/12!): f[0]:=G(x): for n from 1 to 29 do f[n]:=diff(f[n-1], x) od: x:=0: seq(f[n], n=12..28); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 03 2009]
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CROSSREFS
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Sequence in context: A038488 A072393 A085952 this_sequence A093291 A036526 A020316
Adjacent sequences: A129252 A129253 A129254 this_sequence A129256 A129257 A129258
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KEYWORD
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nonn
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AUTHOR
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Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 25 2007
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