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 A097209 #4 Mar 30 2012 17:36:43 %S A097209 9091,909091,909090909090909091,909090909090909090909090909091, %T A097209 9090909090909090909090909090909090909090909090909091, %U A097209 909090909090909090909090909090909090909090909090909090909090909091 %N A097209 Primes of the form (10^p + 1)/11 (corresponding p are in A001562). %C A097209 Equivalently, primes of the form 9090...9091 (A054416(n)-1 copies of 90 followed by 91), the subsequence of all primes in A095372. %C A097209 These primes appear in A187614 because the decimal representation of their reciprocal contains only the digits 0, 1, 8, and 9. %Y A097209 Cf. A001562, A054416, A095372. %K A097209 nonn %O A097209 1,1 %A A097209 _Rick L. Shepherd_, Jul 30 2004