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 A165622 #8 Jul 11 2015 11:01:11
%S A165622 1,4,-8,40,-152,616,-2456,9832,-39320,157288,-629144,2516584,
%T A165622 -10066328,40265320,-161061272,644245096,-2576980376,10307921512,
%U A165622 -41231686040,164926744168,-659706976664,2638827906664,-10555311626648,42221246506600,-168884986026392
%N A165622 a(n)=(-4)*a(n-1)+8 with a(0)=1.
%C A165622 lim_{n -> infinity} a(n)/a(n-1) = -4. [From _Klaus Brockhaus_, Sep 26 2009]
%F A165622 G.f.: (1+7x)/(1+3x-4x^2). a(n)= Sum_{k, 0<=k<=n} A112555(n,k)*3^(n-k). a(0)=1, a(1)=4, a(n)=4*a(n-2)-3*a(n-1).
%F A165622 a(n) = (8-3*(-4)^n)/5. [From _Klaus Brockhaus_ and _Paolo P. Lava_, Sep 26 2009]
%t A165622 NestList[8-4#&,1,30] (* _Harvey P. Dale_, Jul 11 2015 *)
%Y A165622 Cf. A122117,
%K A165622 easy,sign
%O A165622 0,2
%A A165622 _Philippe Deléham_, Sep 22 2009
%E A165622 Corrected and extended by _Harvey P. Dale_, Jul 11 2015