A012137 arctan(arcsin(arctanh(x))) = x + (1/3!)*x^3 + (17/5!)*x^5 + (673/7!)*x^7 + (54305/9!)*x^9 + ...

1, 1, 17, 673, 54305, 7334273, 1497501873, 430436005665, 165573876222529, 82074493484054017, 50922938856050558289, 38644611846710150572193, 35205379514991276523808353, 37909794281251146499011279233

Offset

0,3

Links

Table of n, a(n) for n=0..13.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[ArcTan[ArcSin[ArcTanh[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Jan 18 2020 *)

Crossrefs

Sequence in context: A009158 A012050 A012157 * A171198 A309410 A201311

Adjacent sequences: A012134 A012135 A012136 * A012138 A012139 A012140

Keyword

nonn

Author

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

Status

approved