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 A078060 #7 Mar 19 2025 09:58:41
%S A078060 1,-3,6,-10,14,-16,12,4,-40,104,-200,320,-432,464,-288,-288,1504,
%T A078060 -3584,6592,-10176,13184,-13184,6016,14336,-55040,122112,-215552,
%U A078060 321024,-397824,364544,-87040,-621568,1972224,-4118528,6993920,-10043392,11849728,-9711616,-663552,25026560
%N A078060 Expansion of (1-x)/(1+2*x-2*x^3).
%H A078060 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (-2,0,2).
%F A078060 a(n) = A077988(n)-A077988(n-1). - _R. J. Mathar_, Mar 19 2025
%t A078060 CoefficientList[Series[(1-x)/(1+2x-2x^3),{x,0,60}],x] (* or *) LinearRecurrence[{-2,0,2},{1,-3,6},60] (* _Harvey P. Dale_, Aug 20 2021 *)
%K A078060 sign
%O A078060 0,2
%A A078060 _N. J. A. Sloane_, Nov 17 2002