A013255 Expansion of e.g.f.: cosh(log(x+1)-arctan(x)).

1, 0, 0, 0, 3, -40, 250, -840, 4725, -97200, 1188900, -7994800, 66364375, -1544127000, 26899674750, -278709795000, 3240888275625, -85063768972000, 1886327500213000, -26696356464492000, 405832799545216875, -11978710587284805000, 319632988056247661250, -5765968704482737465000

Offset

0,5

Links

Table of n, a(n) for n=0..23.

Example

1 + 3/4!*x^4 - 40/5!*x^5 + 250/6!*x^6 - 840/7!*x^7 + ... .

Mathematica

With[{nn=20}, CoefficientList[Series[Cosh[Log[x+1]-ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jun 24 2013 *)

Prog

(PARI) my(x='x+O('x^30)); Vec(serlaplace(cosh(log(x+1)-atan(x)))) \\ Michel Marcus, Feb 02 2026

Crossrefs

Sequence in context: A283115 A013257 A013250 * A013256 A013293 A013286

Adjacent sequences: A013252 A013253 A013254 * A013256 A013257 A013258

Keyword

sign

Author

Patrick Demichel

Extensions

Definition clarified by Harvey P. Dale, Jun 24 2013

a(21)-a(23) from Stefano Spezia, Feb 02 2026

Status

approved