A245245 a(n) = C(3*n^2, n^2).

1, 3, 495, 4686825, 2254848913647, 52588547141148893628, 58152371703925106867047535565, 3012179439602547459232394950891834843500, 7255167425905233148164780983569428433097979870294255, 808718755397067598640202627155266231883064669446721506930287016061

Offset: 0

Author

Paul D. Hanna, Jul 15 2014

Keywords

• nonn

Comments

a(n) = A005809(n^2).

Links

• Jens Kruse Andersen, Table of n, a(n) for n = 0..34

Crossrefs

Cf. A245243, A201555, A005809, A213409 (exp).

Programs

Mathematica

Table[Binomial[3*n^2, n^2],{n,0,20}] (* Vaclav Kotesovec, Jul 15 2014 *)

PARI

{a(n)=binomial(3*n^2, n^2)}
for(n=0,15,print1(a(n),", "))

Formula

Logarithmic derivative of A213409 (ignoring initial term a(0) of this sequence).

a(n) ~ 3^(3*n^2+1/2) / (sqrt(Pi) * n * 2^(2*n^2+1)). - Vaclav Kotesovec, Jul 15 2014