A012971 Expansion of e.g.f.: sech(arctan(x)+log(x+1))=1-4/2!*x^2+6/3!*x^3+77/4!*x^4-340/5!*x^5...

1, 0, -4, 6, 77, -340, -3670, 34230, 303425, -5406840, -35315200, 1225800950, 4445446925, -374586782700, 9072379550, 147143429091750, -687446930233375, -71491380123358000, 767045215539726500

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Mathematica

With[{nn=20}, CoefficientList[Series[Sech[ArcTan[x]+Log[x+1]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Dec 26 2013 *)

Crossrefs

Sequence in context: A322150 A319264 A013128 * A197315 A061216 A058163

Adjacent sequences: A012968 A012969 A012970 * A012972 A012973 A012974

Keyword

sign

Author

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

Extensions

Definition clarified by Harvey P. Dale, Dec 26 2013

Status

approved