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A012047
arcsinh(sin(tanh(x)))=x-4/3!*x^3+76/5!*x^5-3536/7!*x^7+317392/9!*x^9...
1
1, -4, 76, -3536, 317392, -47590720, 10785422272, -3441103532288, 1468657322465536, -807408622401283072, 555453404529224756224, -467352773254586231115776, 472081158536303158224572416
OFFSET
0,2
LINKS
FORMULA
a(n) ~ c * (-1)^n * (2*n)! / (sqrt(n) * (arctan(arcsinh(1)))^(2*n)), where c = 1.0522205751764250070089302438417471228756... . - Vaclav Kotesovec, Feb 04 2015
MATHEMATICA
nn = 20; Table[(CoefficientList[Series[ArcSinh[Sin[Tanh[x]]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 04 2015 *)
CROSSREFS
Sequence in context: A024258 A012101 A012080 * A012010 A012155 A350489
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved