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A193385
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E.g.f. cosh( x^2 /2 ) / (1-x).
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1
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1, 1, 2, 6, 27, 135, 810, 5670, 45465, 409185, 4091850, 45010350, 540134595, 7021749735, 98304496290, 1474567444350, 23593081136625, 401082379322625, 7219482827807250, 137170173728337750, 2743403475221484075
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OFFSET
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0,3
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LINKS
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Table of n, a(n) for n=0..20.
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FORMULA
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a(n) ~ cosh( 1/2 ) * n!.
a(n) = (A000266(n) + A130905(n)) / 2.
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MATHEMATICA
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With[{nn=30}, CoefficientList[Series[Cosh[x^2/2]/(1-x), {x, 0, nn}], x] Range[0, nn]!] (* From Harvey P. Dale, May 01 2012 *)
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PROG
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(PARI) {a(n) = if( n<0, 0, n! * polcoeff( cosh( x^2 / 2 + x * O(x^n)) / (1 - x), n))}
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CROSSREFS
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Cf. A000266, A130905.
Sequence in context: A027213 A027237 A027245 * A030961 A030826 A030914
Adjacent sequences: A193382 A193383 A193384 * A193386 A193387 A193388
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KEYWORD
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nonn
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AUTHOR
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Michael Somos, Jul 24 2011
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STATUS
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approved
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