A162602 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^24) * (1-x^27) / (1-x)^9.

1, 9, 45, 164, 486, 1242, 2837, 5931, 11538, 21142, 36828, 61425, 98657, 153297, 231318, 340035, 488232, 686268, 946156, 1281609, 1708047, 2242560, 2903823, 3711960, 4688355, 5855409, 7236243, 8854348, 10733184, 12895731, 15363997

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..126

Programs

Magma

m:=127; R:=PowerSeriesRing(Integers(), m); Coefficients(R!((1-x^3)*(1-x^6)*(1-x^9)*(1-x^12)*(1-x^15)*(1-x^18)*(1-x^21)*(1-x^24)*(1-x^27)/(1-x)^9)); // G. C. Greubel, Jul 06 2018

Mathematica

CoefficientList[ Series[Times @@ (1 - x^(3 Range@9))/(1 - x)^9, {x, 0, 70}], x] (* G. C. Greubel, Jul 06 2018 and slightly modified by Robert G. Wilson v, Jul 23 2018 *)

PARI

x='x+O('x^127); Vec((1-x^3)*(1-x^6)*(1-x^9)*(1-x^12)*(1-x^15)*(1-x^18)*(1-x^21)*(1-x^24)*(1-x^27)/(1-x)^9) \\ G. C. Greubel, Jul 06 2018