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A009132
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Expansion of cosh(ln(1+x))/exp(x).
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1
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1, -1, 2, -7, 31, -161, 976, -6847, 54797, -493201, 4932046, -54252551, 651030667, -8463398737, 118487582396, -1777313736031, 28437019776601, -483429336202337, 8701728051642202, -165332832981201991, 3306656659624039991
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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FORMULA
| a(n) = (-1)^n/2*floor(n!*exp(1)-n+1), n>0. - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 17 2002
E.g.f.: (2+2*x+x^2)/(2*(1+x)*exp(x)) =(1+x/(G(0))/2 ; G(k) = 1 - 1/(1 + x + x^2 - (x*(1+x))^2/(x*(1+x) - (k+1)/(1 + x/G(k+1)))) ; (continued fraction). - Sergei N. Gladkovskii, Dec 28 2011
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MATHEMATICA
| Cosh[ Log[ 1+x ] ]/Exp[ x ]
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CROSSREFS
| Cf. A009578.
Sequence in context: A193320 A030882 A030966 * A125275 A007446 A002872
Adjacent sequences: A009129 A009130 A009131 * A009133 A009134 A009135
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KEYWORD
| sign,easy
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AUTHOR
| R. H. Hardin (rhhardin(AT)att.net)
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EXTENSIONS
| Extended with signs Mar 15 1997 by Olivier Gerard.
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