A009026 Expansion of cos(log(1+x))/cosh(x).

1, 0, -2, 3, 1, 10, -176, 735, -1707, 18828, -251646, 1819895, -10653939, 114938382, -1464499076, 11843786955, -40962861815, -513203638440, 26152049892934, -897502828846005, 24985080257574265, -628449474239226990

Offset

0,3

Links

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

Mathematica

CoefficientList[Series[Cos[Log[1 + x]]*Sech[x], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2015 *)

Prog

(PARI) x='x+O('x^30); Vec(serlaplace( cos(log(1+x))/cosh(x) )) \\ G. C. Greubel, Jul 22 2018
(Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Cos(Log(1+x))/Cosh(x))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Jul 22 2018

Crossrefs

Sequence in context: A107855 A211019 A298401 * A046222 A291647 A074307

Adjacent sequences: A009023 A009024 A009025 * A009027 A009028 A009029

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved