OFFSET
0,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..300
FORMULA
G.f.: (1-x-sqrt(1-6x+x^2))/(2x(1+x));
Conjecture: (n+1)*a(n) +(4-5n)*a(n-1) +(1-5n)*a(n-2) +(n-2)*a(n-3)=0. - R. J. Mathar, Nov 17 2011
a(n) ~ sqrt(48+34*sqrt(2))*(3+2*sqrt(2))^n/(8*sqrt(Pi)*n^(3/2)). - Vaclav Kotesovec, Oct 20 2012
MATHEMATICA
CoefficientList[Series[(1-x-Sqrt[1-6*x+x^2])/(2*x*(1+x)), {x, 0, 20}], x] (* Vaclav Kotesovec, Oct 20 2012 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Oct 09 2009
STATUS
approved