OFFSET
0,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
FORMULA
Recurrence: a(n) = 2*(n-1)*a(n-1) - (n-4)*(n-1)*a(n-2) - 2*(n-2)*(n-1)*a(n-3). - Vaclav Kotesovec, Oct 14 2012
a(n) ~ n!*n*(1+1/e^2)/2. - Vaclav Kotesovec, Oct 14 2012
MATHEMATICA
Table[n!*SeriesCoefficient[E^(-x)*Cosh[x]/(1-x)^2, {x, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Oct 14 2012 *)
With[{nn=30}, CoefficientList[Series[Exp[-x] Cosh[x]/(1-x)^2, {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Mar 24 2020 *)
PROG
(PARI) x='x+O('x^66); Vec(serlaplace(exp(-x)*cosh(x)/(1-x)^2)) \\ Joerg Arndt, May 10 2013
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Sep 19 2003
STATUS
approved