A122767 Expansion of 2*x/(1-6*x-120*x^2+300*x^3).

0, 2, 12, 312, 2712, 50112, 532512, 8394912, 99237312, 1443059712, 18048362112, 251686144512, 3243002406912, 44245843149312, 579129504371712, 7811377482074112, 103090052472256512, 1382166761370918912

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..875

P. Steinbach, Golden fields: a case for the heptagon, Math. Mag. 70 (1997), no. 1, 22-31.

Index entries for linear recurrences with constant coefficients, signature (6,120,-300).

Mathematica

CoefficientList[Series[2x/(1-6x-120x^2+300x^3), {x, 0, 20}], x] (* or *) LinearRecurrence[{6, 120, -300}, {0, 2, 12}, 20] (* Harvey P. Dale, Oct 16 2016 *)

Prog

(PARI) Vec(2*x/(1-6*x-120*x^2+300*x^3)+O(x^99)) \\ Charles R Greathouse IV, Sep 27 2012
(Magma) R<x>:=PowerSeriesRing(Integers(), 30); [0] cat Coefficients(R!( 2*x/(1-6*x-120*x^2+300*x^3) )); // G. C. Greubel, Dec 31 2022
(SageMath)
def A122767_list(prec):
    P.<x> = PowerSeriesRing(ZZ, prec)
    return P( 2*x/(1-6*x-120*x^2+300*x^3) ).list()
A122767_list(30) # G. C. Greubel, Dec 31 2022

Crossrefs

Cf. A078008, A122601.

Sequence in context: A012377 A012425 A012422 * A260321 A094047 A300045

Adjacent sequences: A122764 A122765 A122766 * A122768 A122769 A122770

Keyword

nonn,easy,less

Author

Roger L. Bagula and Gary W. Adamson, Sep 22 2006

Status

approved