OFFSET
1,2
FORMULA
a(n) = Sum_{m=1..n} A046089(n,m)*(-1)^(m-1), n >= 1.
E.g.f.: 1 - exp(-x*(2-x)/(2*(1-x)^2)). Cf. e.g.f. first column of A046089.
a(n) = (3*n-4)*a(n-1) - 3*(n-2)*(n-1)*a(n-2) + (n-3)*(n-2)*(n-1)*a(n-3). - Vaclav Kotesovec, Oct 09 2013
Lim sup n->infinity |a(n)|/(2*n^(n-1/6)*exp(-n^(1/3)/4+3*n^(2/3)/4-n+1/3)/sqrt(3)) = 1. - Vaclav Kotesovec, Oct 09 2013
MATHEMATICA
Rest[CoefficientList[Series[1-E^(-x*(2-x)/(2*(1-x)^2)), {x, 0, 20}], x]* Range[0, 20]!] (* Vaclav Kotesovec, Oct 09 2013 *)
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Wolfdieter Lang Oct 12 2007
STATUS
approved