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 A178558 #2 Mar 31 2012 10:26:16 %S A178558 9199999999,9299999999,9959999999,9995999999,9999499999,9999929999, %T A178558 9999959999,9999999929,10999999999,16999999999,19399999999, %U A178558 19909999999,19991999999,19999399999,19999990999,19999997999,19999999199 %N A178558 Primes with exactly nine 9's. %Y A178558 Cf. A038618, A178550-A178557 %K A178558 nonn,base %O A178558 1,1 %A A178558 _Lekraj Beedassy_, May 29 2010