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A012164
sinh(tan(arcsinh(x))) = x+2/3!*x^3+16/5!*x^5+216/7!*x^7+6400/9!*x^9...
0
1, 2, 16, 216, 6400, 125696, 18156672, -930421504, 394852151296, -97538559528960, 37824762737852416, -16526000392804139008, 8864261701679059992576, -5567468507542446595047424
OFFSET
0,2
FORMULA
a(n) ~ (-1)^n * 2^(2*n+2) * n^(2*n) * cos(tanh(Pi/2)) / ((cosh(Pi)+1) * exp(2*n)). - Vaclav Kotesovec, Oct 30 2013
MATHEMATICA
Table[n!*SeriesCoefficient[Sinh[Tan[ArcSinh[x]]], {x, 0, n}], {n, 1, 40, 2}] (* Vaclav Kotesovec, Oct 30 2013 *)
CROSSREFS
Sequence in context: A012056 A062971 A267782 * A264543 A223638 A188688
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved