OFFSET
0,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..606
FORMULA
a(n) = sum(bin(3*k,k)^2/(2*k+1),k=0..n).
Recurrence: 4*(n+2)^2*(4*n^2+16*n+15) * a(n+2) -(745*n^4+4502*n^3+10181*n^2+10216*n+3840) * a(n+1) +9*(9*n^2+27*n+20)^2 *a(n) = 0.
a(n) ~ 3^(6*n+7)/(713*Pi*n^2*2^(4*n+3)). - Vaclav Kotesovec, Aug 06 2013
MATHEMATICA
Table[Sum[Binomial[3k, k]^2/(2k+1), {k, 0, n}], {n, 0, 20}]
Accumulate[Table[Binomial[3n, n]^2/(2n+1), {n, 0, 20}]] (* Harvey P. Dale, Jul 10 2016 *)
PROG
(Maxima) makelist(sum(binomial(3*k, k)^2/(2k+1), k, 0, n), n, 0, 20);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emanuele Munarini, Apr 08 2011
STATUS
approved