A009128 Expansion of e.g.f. cosh(log(1+x))*cos(x).

1, 0, 0, -3, 7, -30, 194, -1365, 10893, -98028, 980324, -10783575, 129402835, -1682236842, 23551315878, -353269738185, 5652315810841, -96089368784280, 1729608638117192, -32862564124226667, 657251282484533151

Offset

0,4

Links

G. C. Greubel, Table of n, a(n) for n = 0..250

Formula

a(n) ~ n! * (-1)^n * cos(1) / 2. - Vaclav Kotesovec, Jan 22 2015

Mathematica

CoefficientList[Series[((1 + (1 + x)^2)*Cos[x])/(2*(1 + x)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)

Prog

(PARI) x='x+O('x^30); Vec(serlaplace(cosh(log(1+x))*cos(x))) \\ G. C. Greubel, Jul 28 2018
(Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Cosh(Log(1+x))*Cos(x))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Jul 28 2018

Crossrefs

Sequence in context: A019021 A110505 A354518 * A053648 A138862 A080173

Adjacent sequences: A009125 A009126 A009127 * A009129 A009130 A009131

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved