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A012220
cosh(arctan(arcsinh(x)))=1+1/2!*x^2-11/4!*x^4+349/6!*x^6-22007/8!*x^8...
0
1, 1, -11, 349, -22007, 2312601, -365164227, 80916522933, -23968582079343, 9151870592718513, -4378918837383018747, 2566828786036427906445, -1809533477302236292739175, 1510703360292377534570508105
OFFSET
0,3
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Cosh[ArcTan[ArcSinh[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Nov 06 2020 *)
CROSSREFS
Sequence in context: A279238 A192841 A158788 * A012138 A067428 A171630
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved