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A013299
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sinh(log(x+1)-arctanh(x))=-1/2!*x^2-6/4!*x^4-135/6!*x^6-6300/8!*x^8...
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1
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1, 6, 135, 6300, 496125, 58939650, 9833098275, 2191376187000, 628651043645625, 225615874552818750, 99022807341232149375, 52176017395434685252500, 32501310835906189355203125
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Number of degree-2n permutations without odd cycles and with odd number of even cycles, offset 1. E.g.f.: x^2/(2*sqrt(1-x^2)). - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 10 2007
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MATHEMATICA
| nn = 30; Select[Range[0, nn]! CoefficientList[Series[Sinh[Log[1/(1 - x^2)^(1/2)]], {x, 0, nn}], x], # > 0 &] (* Geoffrey Critzer, Jan 15 2012 *)
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CROSSREFS
| Cf. A013302.
Sequence in context: A179564 A050281 A096756 * A013295 A196703 A196852
Adjacent sequences: A013296 A013297 A013298 * A013300 A013301 A013302
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KEYWORD
| nonn
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AUTHOR
| Patrick Demichel (dml(AT)hpfrcu03.france.hp.com)
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