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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
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
0,2
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)
MATHEMATICA
CoefficientList[Series[Times@@(1-x^(3*Range[7]))/(1-x)^7, {x, 0, 40}], x] (* Harvey P. Dale, Oct 08 2015 *)
PROG
(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
(Magma) m:=50; R<x>:=PowerSeriesRing(Integers(), m); F:=(&*[(1-x^(3*k)): k in [1..7]])/(1-x)^7; Coefficients(R!(F)); // G. C. Greubel, Jul 07 2018
CROSSREFS
Cf. A162499.
Sequence in context: A024012 A352900 A163705 * A073363 A247608 A341136
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 02 2009
STATUS
approved