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A012956 arctanh(tan(x)+arcsin(x))=2*x+19/3!*x^3+1033/5!*x^5+139697/7!*x^7... 0
2, 19, 1033, 139697, 35245537, 14290318777, 8497769039329, 6967293521417777, 7532911599857139777, 10384169309400234051945, 17776358796209666513666881, 36997487367543781033857758881 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..11.

FORMULA

a(n) ~ (2*n)! / r^(2*n+1), where r = 0.4711468334470747286400957442399130911292... is the root of the equation tan(r)+arcsin(r) = 1. - Vaclav Kotesovec, Feb 05 2015

MATHEMATICA

nn = 20; Table[(CoefficientList[Series[ArcTanh[ArcSin[x] + Tan[x]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 05 2015 *)

CROSSREFS

Sequence in context: A165937 A128345 A013052 * A012976 A013107 A172028

Adjacent sequences:  A012953 A012954 A012955 * A012957 A012958 A012959

KEYWORD

nonn

AUTHOR

Patrick Demichel (patrick.demichel(AT)hp.com)

STATUS

approved

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Last modified January 26 11:07 EST 2020. Contains 331279 sequences. (Running on oeis4.)