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 A172430 #8 Dec 12 2023 07:43:49 %S A172430 2,1,6,7,0,3,4,9,8,5,2,1,6,7,0,3,4,9,8,5,2,1,6,7,0,3,4,9,8,5,2,1,6,7, %T A172430 0,3,4,9,8,5,2,1,6,7,0,3,4,9,8,5,2,1,6,7,0,3,4,9,8,5,2,1,6,7,0,3,4,9, %U A172430 8,5,2,1,6,7,0,3,4,9,8,5,2,1,6,7,0,3,4,9,8,5,2,1,6,7,0,3,4,9,8,5,2,1,6,7,0,3 %N A172430 Period length 10: repeat 2,1,6,7,0,3,4,9,8,5 . %C A172430 Also the decimal expansion of the rational number 240781665 / 1111111111 . %F A172430 a(n) = A172285(n+1) mod 10. %F A172430 G.f.: (2+x+6*x^2+7*x^3+3*x^5+4*x^6+9*x^7+8*x^8+5*x^9)/ ((1-x) * (1+x) * (x^4+x^3+x^2 +x+1)* (x^4-x^3+x^2-x+1)). %F A172430 a(3*n) = A172423(n+2). %K A172430 nonn,easy %O A172430 0,1 %A A172430 _Paul Curtz_, Feb 02 2010 %E A172430 Edited by _R. J. Mathar_, Feb 11 2010