A162595 G.f. is the polynomial (1-x^3) * (1-x^6) * (1-x^9) * (1-x^12) * (1-x^15) * (1-x^18) * (1-x^21) / (1-x)^7.

1, 7, 28, 83, 203, 434, 839, 1499, 2513, 3997, 6082, 8911, 12635, 17408, 23381, 30696, 39480, 49839, 61852, 75565, 90985, 108075, 126750, 146874, 168259, 190666, 213808, 237355, 260941, 284173, 306641, 327929, 347627, 365343, 380715, 393423

Offset: 0

Author

N. J. A. Sloane, Dec 02 2009

Keywords

• nonn

Comments

This is a row of the triangle in A162499. Only finitely many terms are nonzero.

Links

• G. C. Greubel, Table of n, a(n) for n = 0..77 (complete row)

Crossrefs

Cf. A162499.

Programs

Magma

m:=50; R:=PowerSeriesRing(Integers(), m); F:=(&*[(1-x^(3*k)): k in [1..7]])/(1-x)^7; Coefficients(R!(F)); // G. C. Greubel, Jul 07 2018

Mathematica

CoefficientList[Series[Times@@(1-x^(3*Range[7]))/(1-x)^7,{x,0,40}],x] (* Harvey P. Dale, Oct 08 2015 *)

PARI

x='x+O('x^50); A = prod(k=1, 7, (1-x^(3*k)))/(1-x)^7; Vec(A) \\ G. C. Greubel, Jul 07 2018