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 A077919 #7 Jul 31 2015 12:10:05
%S A077919 1,-1,5,-13,39,-113,331,-965,2819,-8229,24027,-70149,204811,-597973,
%T A077919 1745867,-5097301,14882283,-43450901,126860971,-370388309,1081400363,
%U A077919 -3157299285,9218175915,-26913751125,78578452651,-229420759381,669825926315,-1955650276693,5709793924779
%N A077919 Expansion of (1-x)^(-1)/(1+2*x-2*x^2+2*x^3).
%H A077919 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (-1, 4, -4, 2).
%F A077919 a(0)=1, a(1)=-1, a(2)=5, a(3)=-13, a(n)=a(n-1)+4*a(n-2)-4*a(n-3)+2*a(n-4). - _Harvey P. Dale_, Aug 22 2013
%t A077919 CoefficientList[Series[(1-x)^(-1)/(1+2x-2x^2+2x^3),{x,0,40}],x] (* or *) LinearRecurrence[{-1,4,-4,2},{1,-1,5,-13},40] (* _Harvey P. Dale_, Aug 22 2013 *)
%K A077919 sign
%O A077919 0,3
%A A077919 _N. J. A. Sloane_, Nov 17 2002