A012997 Expansion of e.g.f.: exp(arctan(x)+tan(x))=1+2*x+4/2!*x^2+8/3!*x^3+16/4!*x^4+72/5!*x^5...

1, 2, 4, 8, 16, 72, 544, 3040, 11008, 64896, 1060224, 10595840, 38065152, 87854080, 9708670976, 170663275520, 276991311872, -13108265091072, 283899182678016, 9548887177330688, -9456062364418048

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Mathematica

With[{nn=20}, CoefficientList[Series[Exp[ArcTan[x]+Tan[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jul 07 2019 *)

Crossrefs

Sequence in context: A230863 A322037 A013133 * A013184 A066713 A004000

Adjacent sequences: A012994 A012995 A012996 * A012998 A012999 A013000

Keyword

sign

Author

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

Extensions

Definition clarified by Harvey P. Dale, Jul 07 2019

Status

approved