OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..554
Wadim Zudilin, Ramanujan-type formulae for 1/π: A second wind?, arXiv:0712.1332v2 [math.NT], 2008.
FORMULA
n^3 * a(n) = 8 * (2*n-1) * (8*n^2-8*n+5) * a(n-1) - 4096 * (n-1)^3 * a(n-2) for n > 1.
a(n) ~ Gamma(1/4)^4 * 2^(6*n - 2) / (Pi^(7/2) * sqrt(n)). - Vaclav Kotesovec, Jul 10 2021
PROG
(PARI) {a(n) = sum(k=0, n, binomial(2*k, k)^3*binomial(2*n-2*k, n-k)*2^(4*(n-k)))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Feb 25 2018
STATUS
approved