A012568 - OEIS

%I #9 Jun 22 2022 17:33:20

%S 1,0,-20,-560,-7920,1034880,172569280,12339608320,-1902800305920,

%T -1037015219466240,-208832669083243520,24402030281141555200,

%U 43057075784745711636480,18939654540025835056496640

%N arctanh(sinh(x)*cos(x))=x-20/5!*x^5-560/7!*x^7-7920/9!*x^9...

%F a(n) = A009357(2n+1). - _R. J. Mathar_, Mar 17 2007

%t With[{nn=30},Take[CoefficientList[Series[ArcTanh[Sinh[x]Cos[x]],{x,0,nn}],x] Range[ 0,nn-1]!,{2,-1,2}]] (* _Harvey P. Dale_, Jun 22 2022 *)

%Y Cf. A009357.

%K sign

%O 0,3

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