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 A078053 #13 Mar 19 2025 09:44:35
%S A078053 1,-3,8,-20,50,-124,308,-764,1896,-4704,11672,-28960,71856,-178288,
%T A078053 442368,-1097600,2723360,-6757184,16765888,-41599424,103216256,
%U A078053 -256099584,635432832,-1576632320,3911931136,-9706261248,24083120128,-59754900480,148263518720,-367870598144
%N A078053 Expansion of (1-x)/(1+2*x-2*x^2-2*x^3).
%H A078053 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (-2,2,2).
%F A078053 a(n) = A077981(n)-A077981(n-1). - _R. J. Mathar_, Mar 19 2025
%t A078053 CoefficientList[Series[(1-x)/(1+2x-2x^2-2x^3),{x,0,30}],x] (* or *) LinearRecurrence[{-2,2,2},{1,-3,8},30] (* _Harvey P. Dale_, Dec 17 2017 *)
%K A078053 sign,easy
%O A078053 0,2
%A A078053 _N. J. A. Sloane_, Nov 17 2002