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 A141518 #50 Mar 19 2024 09:31:18
%S A141518 1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,
%T A141518 9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,
%U A141518 7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9,1,3,5,7,9
%N A141518 Period 5: repeat [1, 3, 5, 7, 9].
%C A141518 Final digits of odd numbers in decimal representation: a(n) = A010879(A005408(n)). - _Reinhard Zumkeller_, Apr 11 2010
%H A141518 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,1).
%F A141518 a(n) = 2*(n mod 5) + 1, see PARI code. - _Bruno Berselli_, Jul 25 2018
%F A141518 G.f.: -((9*x^4 + 7*x^3 + 5*x^2 + 3*x + 1)/(x^5 - 1)). - _Kritsada Moomuang_, Sep 06 2018
%F A141518 a(n) = a(n - 5) for n > 4. - _Stefano Spezia_, Sep 07 2018
%t A141518 PadRight[{},120,{1,3,5,7,9}] (* _Harvey P. Dale_, May 06 2014 *)
%t A141518 LinearRecurrence[{0, 0, 0, 0, 1}, {1, 3, 5, 7, 9}, 50] (* or *)
%t A141518 CoefficientList[Series[-((9*x^4 + 7*x^3 + 5*x^2 + 3*x + 1)/(x^5 - 1)), {x, 0, 50}], x] (* _Stefano Spezia_, Sep 07 2018 *)
%o A141518 (PARI) a(n)=1+2*(n%5) \\ _Jaume Oliver Lafont_, Aug 28 2009
%o A141518 (Magma) &cat [[1, 3, 5,7,9]^^25]; // _Vincenzo Librandi_, Jul 25 2018
%K A141518 nonn,easy
%O A141518 0,2
%A A141518 _Paul Curtz_, Aug 11 2008