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URL: https://oeis.org/A012571

⇱ A012571 - OEIS

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A012571
Expansion of arcsin(sinh(x)*sinh(x)).
2
0, 2, 8, 152, 6848, 554912, 70690688, 13009484672, 3265063958528, 1071643508306432, 445538702940858368, 228823524775428872192, 142264706412727018078208, 105297877340452669962493952
OFFSET
0,2
LINKS
FORMULA
a(n) ~ (2*n)! / (2^(1/4) * sqrt(Pi) * n^(3/2) * (log(1+sqrt(2)))^(2*n-1/2)). - Vaclav Kotesovec, Feb 06 2015
EXAMPLE
arcsin(sinh(x)*sinh(x)) = 2/2!*x^2+8/4!*x^4+152/6!*x^6+6848/8!*x^8...
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[ArcSin[Sinh[x]^2], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Dec 11 2013 *)
CROSSREFS
Appears to equal 2 * A012101.
Sequence in context: A102099 A012298 A009596 * A018926 A012432 A071097
KEYWORD
nonn
EXTENSIONS
a(0)=0 prepended by Vaclav Kotesovec, Feb 06 2015
STATUS
approved