A101346 a(n) = binomial(2^n, n-1).

1, 4, 28, 560, 35960, 7624512, 5423611200, 13161885792000, 110859231254749120, 3293259778311548232704, 349928324708588104171703296, 134575849279352109587517966790656, 189165427620415586720308268784807487488, 979739920960712963224129514007339757999308800

Offset

1,2

Links

Andrew Howroyd, Table of n, a(n) for n = 1..50

Formula

G.f.: A(x) = x*Sum_{n>=0} 2^n*log(1+2^n*x)^n/n!. - Paul D. Hanna, Jun 21 2009

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

Maple

seq(binomial(2^n, n-1), n=1..20);

Mathematica

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

Prog

(PARI) a(n)=binomial(2^n, n-1) \\ Paul D. Hanna, Jun 21 2009
(PARI) a(n)=polcoeff(x*sum(k=0, n, 2^k*log(1+2^k*x+x*O(x^n))^k/k!), n) \\ Paul D. Hanna, Jun 21 2009

Crossrefs

Cf. A014070. - Paul D. Hanna, Jun 21 2009

Sequence in context: A111817 A134048 A091969 * A120604 A203279 A081792

Adjacent sequences: A101343 A101344 A101345 * A101347 A101348 A101349

Keyword

nonn

Author

Jorge Coveiro, Dec 25 2004

Extensions

Terms a(13) and beyond from Andrew Howroyd, Feb 12 2020

Status

approved