OFFSET
0,2
COMMENTS
Row sums of number triangle A111965.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..300
FORMULA
a(n) = Sum_{k=0..n} Sum_{j=0..n} C((k+2j-1)/2,j)*C(j,n-j-k)*(-6)^(k-n+2*j) * 5^(n-k-j).
D-finite with recurrence: n*a(n) = 3*(4*n-3)*a(n-1) - 3*(15*n-23)*a(n-2) + 18*(3*n-7) * a(n-3) - 20*(n-3)*a(n-4). - Vaclav Kotesovec, Oct 24 2012
a(n) ~ (sqrt(5)+3)^n/sqrt(5). - Vaclav Kotesovec, Oct 24 2012
MATHEMATICA
CoefficientList[Series[1/(Sqrt[1-6*x+5*x^2]-x), {x, 0, 20}], x] (* Vaclav Kotesovec, Oct 24 2012 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Aug 23 2005
STATUS
approved