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 A077979 Expansion of 1/(1+x+2*x^2+x^3). 7
 1, -1, -1, 2, 1, -4, 0, 7, -3, -11, 10, 15, -24, -16, 49, 7, -89, 26, 145, -108, -208, 279, 245, -595, -174, 1119, -176, -1888, 1121, 2831, -3185, -3598, 7137, 3244, -13920, 295, 24301, -10971, -37926, 35567, 51256, -84464, -53615, 171287, 20407, -309366, 97265, 501060, -386224, -713161 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (-1,-2,-1). FORMULA G.f.: 1 - x/(G(0) + x) where G(k)= 1 - x*(k+1)/(1 - 1/(1 + (k+1)/G(k+1)));(continued fraction, 3-step). - Sergei N. Gladkovskii, Nov 17 2012 a(n) = (-1)^n*A077954(n). - R. J. Mathar, Jul 10 2013 MATHEMATICA CoefficientList[Series[1/(1+x+2x^2+x^3), {x, 0, 50}], x] (* or *) LinearRecurrence[ {-1, -2, -1}, {1, -1, -1}, 50] (* Harvey P. Dale, Apr 18 2016 *) PROG (PARI) my(x='x+O('x^50)); Vec(1/(1+x+2*x^2+x^3)) \\ G. C. Greubel, Jun 25 2019 (Magma) R:=PowerSeriesRing(Integers(), 50); Coefficients(R!( 1/(1+x+2*x^2+x^3) )); // G. C. Greubel, Jun 25 2019 (Sage) (1/(1+x+2*x^2+x^3)).series(x, 50).coefficients(x, sparse=False) # G. C. Greubel, Jun 25 2019 (GAP) a:=[1, -1, -1];; for n in [4..50] do a[n]:=-a[n-1]-2*a[n-2]-a[n-3]; od; a; # G. C. Greubel, Jun 25 2019 CROSSREFS Cf. A077954. Sequence in context: A011017 A348508 A077954 * A297108 A307626 A122161 Adjacent sequences: A077976 A077977 A077978 * A077980 A077981 A077982 KEYWORD sign,easy AUTHOR N. J. A. Sloane, Nov 17 2002 STATUS approved

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Last modified March 29 15:46 EDT 2023. Contains 361599 sequences. (Running on oeis4.)