A132684 a(n) = binomial(2^n + n + 1, n).

1, 4, 21, 220, 5985, 501942, 143218999, 145944307080, 542150225230185, 7398714129087308170, 372134605932348010322571, 69146263065062394421802892300, 47589861944854471977019273909187085

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..50

Formula

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

G.f.: Sum_{n>=0} (-log(1 - 2^n*x))^n / ((1 - 2^n*x)^2*n!). - Paul D. Hanna, Feb 25 2009

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

Example

From Paul D. Hanna, Feb 25 2009: (Start)
G.f.: A(x) = 1 + 4*x + 21*x^2 + 220*x^3 + 5985*x^4 + 501942*x^5 +...
A(x) = 1/(1-x)^2 - log(1-2x)/(1-2x)^2 + log(1-4x)^2/((1-4x)^2*2!) - log(1-8x)^3/((1-8x)^2*3!) +- ... (End)

Maple

A132684:= n-> binomial(2^n +n+1, n); seq(A132684(n), n=0..20); # G. C. Greubel, Mar 14 2021

Mathematica

Table[Binomial[2^n+n+1, n], {n, 0, 20}] (* Harvey P. Dale, Nov 10 2011 *)

Prog

(PARI) a(n)=binomial(2^n+n+1, n)
(PARI) {a(n)=polcoeff(sum(m=0, n, (-log(1-2^m*x))^m/((1-2^m*x +x*O(x^n))^2*m!)), n)} \\ Paul D. Hanna, Feb 25 2009
(Sage) [binomial(2^n +n+1, n) for n in (0..20)] # G. C. Greubel, Mar 14 2021
(Magma) [Binomial(2^n +n+1, n): n in [0..20]]; // G. C. Greubel, Mar 14 2021

Crossrefs

Sequences of the form binomial(2^n +p*n +q, n): A136556 (0,-1), A014070 (0,0), A136505 (0,1), A136506 (0,2), A060690 (1,-1), A132683 (1,0), this sequence (1,1), A132685 (2,0), A132686 (2,1), A132687 (3,-1), A132688 (3,0), A132689 (3,1).

Cf. A136555.

Cf. A066384. - Paul D. Hanna, Feb 25 2009

Sequence in context: A041667 A286883 A217144 * A357857 A032074 A197662

Adjacent sequences: A132681 A132682 A132683 * A132685 A132686 A132687

Keyword

nonn

Author

Paul D. Hanna, Aug 26 2007

Status

approved