A177400 a(n) = binomial(n*2^n, n).

1, 2, 28, 2024, 635376, 820384032, 4281625192384, 89850821311025280, 7571365534761592422144, 2561263066959640762657702400, 3477982739629565890806006777904128

Offset: 0

Author

Paul D. Hanna, Jun 26 2010

Keywords

• nonn

Crossrefs

Cf. A177410, A177411.

Cf. A136463. - Paul D. Hanna, Jul 03 2010

Programs

Mathematica

Table[Binomial[n 2^n,n],{n,0,20}] (* Harvey P. Dale, Jan 15 2022 *)

PARI

{a(n)=binomial(n*2^n,n)}

PARI

{a(n)=polcoeff(sum(k=0, n, n^k*log(1+2^k*x +x*O(x^n))^k/k!), n)} \\ Paul D. Hanna, Jul 03 2010

Formula

a(n) = [x^n] (1 + x)^(n*2^n).

a(n) = [x^n] Sum_{k=0..n} n^k * log(1 + 2^k*x)^k/k!. - Paul D. Hanna, Jul 03 2010