A012867 Numerators of coefficients in Taylor series expansion of log(cotan(x)*arctan(x)).

0, -2, 1, -313, 317, -7813, 6895597, -61916737, 10655226077, -41786390722733, 613552118040217, -41640337444573141, 6761598195684420293, -140000933764069408573, 81775784693678733811, -368555295637618487393608489, 41000094641259185671029500461, -243445658683280857337557514581

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..250

Example

-(2/3)*x^2 + (1/15)*x^4 - (313/2835)*x^6 + (317/5670)*x^8 - (7813/155925)*x^10 + ...

Mathematica

Numerator[Take[CoefficientList[Series[Log[Cot[x]ArcTan[x]], {x, 0, 40}], x], {1, -1, 2}]] (* Harvey P. Dale, May 18 2012 *)

Crossrefs

Cf. A202621.

Sequence in context: A098879 A331818 A261437 * A178393 A272538 A087037

Adjacent sequences: A012864 A012865 A012866 * A012868 A012869 A012870

Keyword

sign,frac

Author

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

Extensions

Corrected by N. J. A. Sloane, Dec 21 2011

Status

approved