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 A166122 #16 Sep 03 2022 21:04:07
%S A166122 1,2,-3,22,-103,522,-2603,13022,-65103,325522,-1627603,8138022,
%T A166122 -40690103,203450522,-1017252603,5086263022,-25431315103,127156575522,
%U A166122 -635782877603,3178914388022,-15894571940103,79472859700522
%N A166122 a(n) = (7-(-5)^n)/6.
%H A166122 G. C. Greubel, <a href="/A166122/b166122.txt">Table of n, a(n) for n = 0..1000</a>
%H A166122 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (-4,5).
%F A166122 a(n) = 5*a(n-2) - 4*a(n-1), a(0)= 1, a(1)= 2, for n>1.
%F A166122 a(n) = 7-5*a(n-1), a(0)=1.
%F A166122 a(n) = a(n-1)+(-5)^(n-1), a(0)=1.
%F A166122 O.g.f.: (1+6*x)/(1+4*x-5*x^2).
%F A166122 E.g.f.: (7*exp(x)-exp(-5*x))/6.
%t A166122 LinearRecurrence[{-4,5},{1,2},30] (* _Harvey P. Dale_, Mar 10 2016 *)
%t A166122 Table[(7 - (-5)^n)/6, {n, 24}] (* or *)
%t A166122 CoefficientList[Series[(1 + 6 x)/(1 + 4 x - 5 x^2), {x, 0, 24}], x] (* _Michael De Vlieger_, Apr 27 2016 *)
%Y A166122 Cf. A084222, A084247, A166114.
%K A166122 sign,easy
%O A166122 0,2
%A A166122 _Philippe Deléham_, Oct 07 2009