OFFSET
0,2
COMMENTS
Self-convolution of A245927.
Limit a(n+1)/a(n) = 7 + 4*sqrt(3).
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..870
FORMULA
a(n) ~ (26 + 15*sqrt(3)) * (7 + 4*sqrt(3))^n / 24 * (1 - 1/(3^(1/4)*sqrt(Pi*n/2))). - Vaclav Kotesovec, Aug 17 2014
D-finite with recurrence: (n+1)*a(n) +7*(-4*n-1)*a(n-1) +99*(2*n-1)*a(n-2) +7*(-4*n+5)*a(n-3) +(n-2)*a(n-4)=0. - R. J. Mathar, Jan 23 2020
EXAMPLE
G.f.: A(x) = 1 + 18*x + 279*x^2 + 4132*x^3 + 59949*x^4 + 860022*x^5 +...
MATHEMATICA
CoefficientList[Series[(1 - x - Sqrt[1 - 14*x + x^2])/(6*x*(1 - 14*x + x^2)), {x, 0, 50}], x] (* G. C. Greubel, Feb 14 2017 *)
PROG
(PARI) {a(n)=polcoeff( (1-x - sqrt(1-14*x+x^2 +x^2*O(x^n))) / (6*x*(1-14*x+x^2 +x*O(x^n))), n)}
for(n=0, 20, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 16 2014
STATUS
approved