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 A172423 #13 Dec 12 2023 08:09:59 %S A172423 0,9,2,7,4,5,6,3,8,1,0,9,2,7,4,5,6,3,8,1,0,9,2,7,4,5,6,3,8,1,0,9,2,7, %T A172423 4,5,6,3,8,1,0,9,2,7,4,5,6,3,8,1 %N A172423 Period length 10: repeat 0,9,2,7,4,5,6,3,8,1. %C A172423 Also the decimal expansion of 103050709/1111111111. %H A172423 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,0,1). %F A172423 a(2n) = A135033(n-1). %F A172423 a(2n+1) = A096230(n+1). %F A172423 a(n+2) = A172430(3*n). %F A172423 G.f.: -x*(9+2*x+7*x^2+4*x^3+5*x^4+6*x^5+3*x^6+8*x^7+x^8) / ( (x-1)*(1+x)*(x^4+x^3+x^2+x+1)*(x^4-x^3+x^2-x+1) ). %K A172423 nonn,easy %O A172423 0,2 %A A172423 _Paul Curtz_, Feb 02 2010