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A012039
sinh(sin(arcsinh(x))) = x-1/3!*x^3+1/5!*x^5+111/7!*x^7-9407/9!*x^9...
0
1, -1, 1, 111, -9407, 957791, -131065791, 23876150351, -5645293077119, 1689130316350143, -625455343415905919, 281176376077651011119, -150982531394396522439999, 95493861079696805301099551
OFFSET
0,4
FORMULA
a(n) ~ (-1)^n * cos(sinh(Pi/2)) * cosh(Pi/2) * 2^(2*n+1) * n^(2*n) / exp(2*n). - Vaclav Kotesovec, Oct 30 2013
MATHEMATICA
Table[n!*SeriesCoefficient[Sinh[Sin[ArcSinh[x]]], {x, 0, n}], {n, 1, 40, 2}] (* Vaclav Kotesovec, Oct 30 2013 *)
With[{nn=30}, Take[CoefficientList[Series[Sinh[Sin[ArcSinh[x]]], {x, 0, nn}], x] Range[ 0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Mar 18 2023 *)
CROSSREFS
Sequence in context: A232080 A332914 A129051 * A286117 A286083 A286731
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved