A136466 Row 2 of square array A136462: a(n) = C(3*2^(n-1), n) for n>=0.

1, 3, 15, 220, 10626, 1712304, 927048304, 1708566412608, 10895665708319184, 244373929798154341120, 19561373281624772727757056, 5658395223117478029148167447552, 5975982733408602667847206514763365888

Offset: 0

Author

Paul D. Hanna, Dec 31 2007

Keywords

• nonn

Comments

a(n) is found in row n, column 0, of matrix cube A136467^3 for n>=0.

Crossrefs

Cf. A136462; other rows: A136465, A014070, A101346; A136467.

Programs

Mathematica

Table[Binomial[3*2^(n-1),n], {n,0,15}] (* Vaclav Kotesovec, Jul 02 2016 *)

PARI

a(n)=binomial(3*2^(n-1),n)

PARI

/* T(n,k) = Coefficient of x^k in series: */ a(n)=polcoeff(sum(i=0,n,(3/2)^i*log(1+2^i*x +x*O(x^n))^i/i!),n)

Formula

a(n) = [x^n] Sum_{i>=0} (3/2)^i * log(1 + 2^i*x)^i/i!.

a(n) ~ 3^n * 2^(n*(n-1)) / n!. - Vaclav Kotesovec, Jul 02 2016