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 A166114 #16 May 03 2019 08:28:08
%S A166114 1,2,-2,14,-50,206,-818,3278,-13106,52430,-209714,838862,-3355442,
%T A166114 13421774,-53687090,214748366,-858993458,3435973838,-13743895346,
%U A166114 54975581390,-219902325554,879609302222,-3518437208882,14073748835534,-56294995342130
%N A166114 a(n) = (6-(-4)^n)/5.
%H A166114 Georg Fischer, <a href="/A166114/b166114.txt">Table of n, a(n) for n = 0..1000</a>
%H A166114 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (-3,4).
%F A166114 a(n) = 4*a(n-2) - 3*a(n-1), a(0)= 1, a(1)= 2, for n>1.
%F A166114 a(n) = 6 - 4*a(n-1), a(0)=1.
%F A166114 a(n) = a(n-1) + (-4)^(n-1), a(0)=1.
%F A166114 G.f.: (1+5x)/(1+3x-4x^2).
%F A166114 E.g.f.: (6*exp(x) - exp(-4x))/5.
%t A166114 Table[(6 - (-4)^n)/5, {n, 0, 100}] (* _G. C. Greubel_, Apr 24 2016 *)
%o A166114 (PARI) a(n)=(6-(-4)^n)/5 \\ _Charles R Greathouse IV_, Apr 28 2016
%Y A166114 Cf. A084222, A084247.
%K A166114 easy,sign
%O A166114 0,2
%A A166114 _Philippe Deléham_, Oct 06 2009
%E A166114 a(12) onward changed by _Georg Fischer_, May 03 2019