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A170935
b(n)*b(n+1), where b() = A000930().
1
1, 1, 2, 6, 12, 24, 54, 117, 247, 532, 1148, 2460, 5280, 11352, 24381, 52353, 112462, 241570, 518840, 1114416, 2393694, 5141385, 11043135, 23719608, 50947336, 109429624, 235043840, 504850560, 1084367865, 2329112625, 5002699050, 10745292366, 23079802756, 49573086472
OFFSET
0,3
FORMULA
G.f.: 1 / ((x^3-x^2-1)*(x^3+2*x^2+x-1)). - Colin Barker, Jul 25 2013
MATHEMATICA
CoefficientList[Series[1/((x^3 - x^2 - 1)*(x^3 + 2*x^2 + x - 1)), {x, 0, 50}], x] (* G. C. Greubel, Apr 26 2017 *)
LinearRecurrence[{1, 1, 3, 1, -1, -1}, {1, 1, 2, 6, 12, 24}, 40] (* Harvey P. Dale, Aug 27 2019 *)
PROG
(PARI) x='x+O('x^50); Vec(1/((x^3-x^2-1)*(x^3+2*x^2+x-1))) \\ G. C. Greubel, Apr 26 2017
CROSSREFS
Sequence in context: A133953 A350293 A122863 * A277173 A163264 A335327
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Feb 11 2010
STATUS
approved