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A009236
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E.g.f. exp(sinh(x)^2) (even powers only).
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0
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1, 2, 20, 392, 12560, 579872, 36034880, 2874676352, 284538241280, 34058188677632, 4831480473359360, 799233222752602112, 152126941229960990720, 32947584100184816033792
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| a(n)=sum(k=1..n, sum(i=0..2*k, (-1)^i*(k-i)^(2*n)*binomial(2*k,i))*(2^(2*(n-k))/k!)), n>0, a(0)=1. [Vladimir Kruchinin, Jun 06 2011]
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MATHEMATICA
| Exp[ Sinh[ x ]^2 ] (* Even Part *)
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PROG
| (Maxima)
a(n):=sum(sum((-1)^i*(k-i)^(2*n)*binomial(2*k, i), i, 0, 2*k)*(2^(2*(n-k))/k!), k, 1, n); [Vladimir Kruchinin, Jun 06 2011]
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CROSSREFS
| Sequence in context: A060164 A084948 A187661 * A078698 A090728 A185281
Adjacent sequences: A009233 A009234 A009235 * A009237 A009238 A009239
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KEYWORD
| nonn
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AUTHOR
| R. H. Hardin (rhhardin(AT)att.net)
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EXTENSIONS
| Extended and signs tested Mar 15 1997 by Olivier Gerard.
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