This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A077959 #18 Sep 08 2022 08:45:08
%S A077959 1,0,0,-2,0,0,4,0,0,-8,0,0,16,0,0,-32,0,0,64,0,0,-128,0,0,256,0,0,
%T A077959 -512,0,0,1024,0,0,-2048,0,0,4096,0,0,-8192,0,0,16384,0,0,-32768,0,0,
%U A077959 65536,0,0,-131072,0,0,262144,0,0,-524288,0,0,1048576,0,0,-2097152,0,0,4194304,0,0,-8388608,0
%N A077959 Expansion of 1/(1+2*x^3).
%H A077959 G. C. Greubel, <a href="/A077959/b077959.txt">Table of n, a(n) for n = 0..1002</a>
%H A077959 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, -2).
%F A077959 a(0)=1, a(1)=0, a(2)=0, a(n) = -2*a(n-3). - _Harvey P. Dale_, Dec 19 2012
%F A077959 a(n) = (-1)^n * A077958(n). - _R. J. Mathar_, Mar 04 2018
%t A077959 CoefficientList[Series[1/(1+2x^3),{x,0,80}],x] (* or *) LinearRecurrence[ {0,0,-2},{1,0,0},80] (* _Harvey P. Dale_, Dec 19 2012 *)
%o A077959 (PARI) Vec(1/(1+2*x^3)+O(x^80)) \\ _Charles R Greathouse IV_, Sep 27 2012
%o A077959 (Magma) R<x>:=PowerSeriesRing(Integers(), 80); Coefficients(R!( 1/(1+2*x^3) )); // _G. C. Greubel_, Jun 23 2019
%o A077959 (Sage) (1/(1+2*x^3)).series(x, 80).coefficients(x, sparse=False) # _G. C. Greubel_, Jun 23 2019
%Y A077959 Cf. A077958.
%K A077959 sign,easy
%O A077959 0,4
%A A077959 _N. J. A. Sloane_, Nov 17 2002