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 A012031 arcsinh(sin(sinh(x)))=x-1/3!*x^3+1/5!*x^5-113/7!*x^7+4033/9!*x^9... 1
 1, -1, 1, -113, 4033, -307297, 32041153, -4722808145, 919792817281, -229762987386049, 71595055755086977, -27226195625057526833, 12411835138553868048961, -6681718218812850626513185 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Vaclav Kotesovec, Table of n, a(n) for n = 0..226 FORMULA a(n) ~ (2*n)! * (-1)^n * c / (sqrt(n) * (arcsin(log(1+sqrt(2))))^(2*n)), where c = 0.444000919811565867306663265... . - Vaclav Kotesovec, Feb 03 2015 MATHEMATICA nn = 20; Table[(CoefficientList[Series[ArcSinh[Sin[Sinh[x]]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 03 2015 *) CROSSREFS Sequence in context: A008362 A262074 A200854 * A283781 A350054 A250052 Adjacent sequences:  A012028 A012029 A012030 * A012032 A012033 A012034 KEYWORD sign AUTHOR Patrick Demichel (patrick.demichel(AT)hp.com) STATUS approved

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Last modified June 28 07:25 EDT 2022. Contains 354903 sequences. (Running on oeis4.)