A321344 - OEIS

A321344

Expansion of 1/(1 - x) * Product_{k>=0} 1/(1 - x^(3^k))^(3^(k+1)).

1, 4, 10, 29, 71, 146, 309, 615, 1119, 2068, 3709, 6289, 10793, 18206, 29513, 48201, 77757, 121668, 191257, 297847, 452761, 690524, 1045661, 1552697, 2310786, 3419082, 4976739, 7254407, 10522736, 15052376, 21552205, 30731101, 43297942, 61039239, 85741503, 119191245

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

Also the coefficient of x^(3*n) in the expansion of Product_{k>=0} 1/(1 - x^(3^k))^(3^k).

LINKS

Table of n, a(n) for n=0..35.

EXAMPLE

Product_{k>=0} 1/(1 - x^(3^k))^(3^k) = 1 + x + x^2 + 4*x^3 + 4*x^4 + 4*x^5 + 10*x^6 + 10*x^7 + 10*x^8 + 29*x^9 + 29*x^10 + 29*x^11 + ... .

PROG

(PARI) seq(n)={Vec(1/((1 - x)*prod(k=0, logint(n, 3), (1 - x^(3^k) + O(x*x^n))^(3^(k+1)))))} \\ Andrew Howroyd, Nov 06 2018

CROSSREFS