A292414 a(n) = [x^n] Product_{k>=1} (1 + 2^n*x^k).

1, 2, 4, 72, 272, 2080, 270400, 2146432, 33751296, 403702272, 1103810790400, 17635156690944, 563431073648640, 13515197331283968, 360331952265379840, 37785849814204784082944, 1209091844251972299456512, 77374499118322174520328192, 3713890953695657990811811840

Offset

0,2

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..183

Formula

Conjecture: log(a(n)) ~ sqrt(2)*log(2)*n^(3/2). - Vaclav Kotesovec, Aug 22 2018

Mathematica

nmax = 20; Table[SeriesCoefficient[Product[(1+2^n*x^k), {k, 1, n}], {x, 0, n}], {n, 0, nmax}]

Prog

(PARI) {a(n)= polcoef(prod(k=1, n, (1+2^n*x^k +x*O(x^n))), n)};
for(n=0, 20, print1(a(n), ", ")) \\ G. C. Greubel, Feb 02 2019

Crossrefs

Cf. A292304, A292415, A292416.

Sequence in context: A066974 A270583 A018373 * A053550 A018378 A023175

Adjacent sequences: A292411 A292412 A292413 * A292415 A292416 A292417

Keyword

nonn,look

Author

Vaclav Kotesovec, Sep 16 2017

Status

approved