A013445 tanh(tan(x)-arctan(x)) = 4/3!*x^3 - 8/5!*x^5 + 992/7!*x^7 - 68224/9!*x^9 + ...

4, -8, 992, -68224, 5165312, -1019810816, 186916489216, -51926843359232, 18052796043493376, -7489482677372846080, 3888725315407646818304, -2359682003031000489132032, 1689998575261701932163530752

Offset

3,1

Links

Table of n, a(n) for n=3..15.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Tanh[Tan[x]-ArcTan[x]], {x, 0, nn}], x]Range[0, nn-1]!, {4, -1, 2}]] (* Harvey P. Dale, Mar 11 2012 *)

Crossrefs

Sequence in context: A013443 A013442 A013441 * A201386 A009511 A057841

Adjacent sequences: A013442 A013443 A013444 * A013446 A013447 A013448

Keyword

sign

Author

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

Status

approved