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 A068694 #7 Dec 05 2013 19:55:12 %S A068694 7,97,997,9973,99991,999979,9999991,99999971,999999937,9999999557, %T A068694 99999999977,999999999959,9999999999971,99999999999973, %U A068694 999999999999577,9999999999999937,99999999999999997,999999999999999737 %N A068694 Largest n-digit prime with all odd digits. %F A068694 a(n)<=A003618(n). - _R. J. Mathar_, May 18 2007 %Y A068694 Cf. A068690, A068691, A068692, A068693. %Y A068694 Cf. A003618. %K A068694 base,nonn %O A068694 1,1 %A A068694 _Amarnath Murthy_, Mar 03 2002 %E A068694 More terms from _Sascha Kurz_, Mar 17 2002