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

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

Offset

0,2

Comments

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

Links

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

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

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A198659 A142801 A057632 * A024045 A334304 A255017

Adjacent sequences: A245242 A245243 A245244 * A245246 A245247 A245248

Keyword

nonn

Author

Paul D. Hanna, Jul 15 2014

Status

approved