A211182 E.g.f. 1-x*(1-x)*(tan(x)+sec(x)).

1, -1, 0, 3, 4, 15, 54, 245, 1240, 7119, 45290, 317229, 2423268, 20055607, 178747646, 1706919045, 17386518448, 188166282399, 2156226542802, 26081233464413, 332076574410940, 4439536794401415, 62178531797006438, 910433903838620853, 13910405388847664904

Offset

0,4

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..202

Formula

a(n) ~ n! * (Pi-2)*2^n/Pi^n. - Vaclav Kotesovec, Feb 12 2013

Mathematica

With[{nn = 24}, CoefficientList[ Series[1 - x (1 - x) (Tan[x] + Sec[x]), {x, 0, nn}], x] Range[0, nn]!]
Join[{1, -1, 0}, Table[-n * (((n-1)*EulerE[n-2] + 2^(n-1)*EulerE[n-1, 0]) * Cos[Pi*n/2] + (EulerE[n-1] - 2^(n-2)*(n-1)*EulerE[n-2, 0]) * Sin[Pi*n/2]), {n, 3, 30}]] (* Benedict W. J. Irwin, Jul 28 2016 *)

Crossrefs

Cf. A034428.

Sequence in context: A042771 A176755 A299684 * A135962 A171062 A171061

Adjacent sequences: A211179 A211180 A211181 * A211183 A211184 A211185

Keyword

sign,easy

Author

LtC. R. Scott Patterson (aa737drvr(AT)comcast.net) and Robert G. Wilson v, Feb 02 2013

Status

approved