OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..425
FORMULA
E.g.f.: e^x*(1-e^x)/((2-e^x)*(1-2*e^x)).
a(n) = Sum_{k=0..n} (-1)^(n-k) * k! * S2(n,k) * A001045(k).
a(n) ~ n! * (2-(-1)^n)/(6*log(2)^(n+1)). - Vaclav Kotesovec, Sep 26 2013
MAPLE
a:= n-> -add((-1)^k*k!*Stirling2(n+1, k+1)*(<<0|1>, <2|1>>^k)[1, 2], k=0..n):
seq(a(n), n=0..23); # Alois P. Heinz, May 09 2018
MATHEMATICA
CoefficientList[Series[E^x*(1-E^x)/((2-E^x)*(1-2*E^x)), {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Sep 26 2013 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 20 2005
STATUS
approved