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 A091086 #27 Jan 01 2024 11:27:19
%S A091086 0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,
%T A091086 2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,
%U A091086 0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0,1,2,5,0
%N A091086 a(n) = A000975(n) mod 10.
%C A091086 A000975(0), A000975(1), A000975(2), A000975(3) repeating.
%H A091086 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,1).
%F A091086 G.f.: x*(1 + 2*x + 5*x^2)/(1 - x^4).
%F A091086 E.g.f.: 2*exp(x) - exp(-x) - cos(x) - 2*sin(x).
%F A091086 a(n) = 2 - (-1)^n - cos(Pi*n/2) - 2*sin(Pi*n/2).
%F A091086 a(n+4) = a(n). - _G. C. Greubel_, Sep 26 2017
%F A091086 2*a(n) = (n mod 2) + (n mod 4)^2. - _Bruno Berselli_, Oct 18 2018
%t A091086 CoefficientList[Series[x (1 + 2 x + 5 x^2)/(1 - x^4), {x, 0, 50}], x] (* _G. C. Greubel_, Sep 26 2017 *)
%t A091086 PadRight[{},120,{0,1,2,5}] (* _Harvey P. Dale_, Apr 30 2022 *)
%o A091086 (PARI) x='x+O('x^50); Vec(x*(1+2*x+5*x^2)/(1-x^4)) \\ _G. C. Greubel_, Sep 26 2017
%K A091086 nonn,easy
%O A091086 0,3
%A A091086 _Paul Barry_, Dec 18 2003