A013447 - OEIS

%I #6 Mar 19 2016 11:03:13

%S 1,0,0,160,-1792,484224,-15071232,6570936320,-461050544128,

%T 285431558799360,-41198126773469184,31834693166688370688,

%U -8575650915562515595264,7808988993818084822220800

%N sec(tan(x)-arctan(x))=1+160/6!*x^6-1792/8!*x^8+484224/10!*x^10...

%t With[{nn=30},Take[CoefficientList[Series[Sec[Tan[x]-ArcTan[x]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Mar 19 2016 *)

%K sign

%O 0,4

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