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 A091084 #22 May 11 2024 17:31:14
%S A091084 0,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,
%T A091084 1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,
%U A091084 5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5,1,1,3,5
%N A091084 a(n) = A001045(n) mod 10.
%C A091084 A001045(0), followed by A001045(1), A001045(2), A001045(3), A001045(4) repeating.
%C A091084 Decimal expansion of 227/19998. - _Elmo R. Oliveira_, May 11 2024
%H A091084 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,1).
%F A091084 G.f.: x*(1+x+3x^2+5x^3)/(1-x^4); e.g.f.: 2*cos(x) - sin(x) + exp(-x)/2 + 5*exp(x)/2 - 5; a(n) = 2*cos(Pi*n/2) - sin(Pi*n/2) + (-1)^n/2 + 5/2 - 5*0^n.
%F A091084 a(n) = a(n-4) for n > 4. - _Elmo R. Oliveira_, May 11 2024
%t A091084 CoefficientList[Series[x (1+x+3x^2+5x^3)/(1-x^4), {x,0,150}], x] (* _Harvey P. Dale_, Mar 26 2011 *)
%Y A091084 Cf. A001045.
%K A091084 easy,nonn
%O A091084 0,4
%A A091084 _Paul Barry_, Dec 18 2003