OFFSET
0,2
COMMENTS
FORMULA
G.f.: ((2-x)/(1-2*x) + x*sqrt(1-4*x^2)/(1-2*x)^2)/2.
Conjecture: (n-1)*a(n) - 2*n*a(n-1) + 4*(4-n)*a(n-2) + 8*(n-3)*a(n-3) = 0. - R. J. Mathar, Oct 25 2012
a(n) ~ 2^(n - 1/2) * sqrt(n/Pi) * (1 + 3*sqrt(2*Pi/n)/4). - Vaclav Kotesovec, Apr 11 2021
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Oct 23 2007
STATUS
approved