OFFSET
0,3
FORMULA
a(n) ~ n! * (-1)^n / (2*exp(1)). - Vaclav Kotesovec, Jan 22 2015
a(n) = ((-1)^n * A000387(n)) + 1. - Christian Krause, Jan 05 2024
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Exp[x]*Cosh[Log[1+x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Sep 02 2016 *)
CoefficientList[Series[(E^x*(1 + (1 + x)^2))/(2*(1 + x)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)
PROG
(PARI) my(x='x+O('x^66)); Vec(serlaplace(exp(x)*cosh(log(1+x)))) \\ Joerg Arndt, Jan 05 2024
CROSSREFS
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
Prior Mathematica program replaced by Harvey P. Dale, Sep 02 2016
STATUS
approved