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 A078055 #11 Mar 19 2025 09:46:56
%S A078055 1,-3,8,-24,70,-204,596,-1740,5080,-14832,43304,-126432,369136,
%T A078055 -1077744,3146624,-9187008,26822752,-78312768,228645056,-667561152,
%U A078055 1949037952,-5690488320,16614174848,-48507402240,141624130816,-413491415808,1207245897728,-3524722888704,10290920404480
%N A078055 Expansion of (1-x)/(1+2*x-2*x^2+2*x^3).
%H A078055 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (-2, 2, -2).
%F A078055 a(0)=1, a(1)=-3, a(2)=8, a(n)=-2*a(n-1)+2*a(n-2)-2*a(n-3). - _Harvey P. Dale_, Mar 06 2013
%F A078055 a(n) = A077984(n)-A077984(n-1). - _R. J. Mathar_, Mar 19 2025
%t A078055 CoefficientList[Series[(1-x)/(1+2x-2x^2+2x^3),{x,0,50}],x] (* or *) LinearRecurrence[{-2,2,-2},{1,-3,8},50] (* _Harvey P. Dale_, Mar 06 2013 *)
%K A078055 sign,easy
%O A078055 0,2
%A A078055 _N. J. A. Sloane_, Nov 17 2002