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A117791
Expansion of 1/(1 - x - x^2 + x^4 - x^6).
33
1, 1, 2, 3, 4, 6, 9, 13, 20, 30, 45, 68, 102, 153, 230, 345, 518, 778, 1168, 1754, 2634, 3955, 5939, 8918, 13391, 20108, 30194, 45339, 68081, 102230, 153508, 230507, 346128, 519744, 780445, 1171912, 1759737, 2642412, 3967832, 5958076, 8946616, 13434192
OFFSET
0,3
FORMULA
a(n) = a(n-1) + a(n-2) - a(n-4) + a(n-6). - Ilya Gutkovskiy, Nov 16 2016
MAPLE
seq(coeff(series(1/(1 -x -x^2 +x^4 -x^6), x, n+1), x, n), n = 0..50); # G. C. Greubel, Dec 05 2019
MATHEMATICA
CoefficientList[Series[1/(1 -x -x^2 +x^4 -x^6), {x, 0, 50}], x]
PROG
(PARI) Vec(1/(1 -x -x^2 +x^4 -x^6)+O(x^50)) \\ Charles R Greathouse IV, Sep 23 2012
(Magma) R<x>:=PowerSeriesRing(Integers(), 50); Coefficients(R!(1/(1-x-x^2+x^4-x^6))); // G. C. Greubel, Nov 03 2018
(Sage)
def A117791_list(prec):
P.<x> = PowerSeriesRing(ZZ, prec)
return P( 1/(1 -x -x^2 +x^4 -x^6) ).list()
A117791_list(50) # G. C. Greubel, Dec 05 2019
KEYWORD
nonn,easy
AUTHOR
Roger L. Bagula, Apr 15 2006
EXTENSIONS
Edited by N. J. A. Sloane, Nov 08 2006
STATUS
approved