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 A178003 #5 Mar 31 2012 10:26:16 %S A178003 5,59,557,5557,75557,555557,9555551,55555559,855555559,5555555557, %T A178003 75555555557,555555555559,5555555555551,59555555555557, %U A178003 555555555555557,6555555555555553,55556555555555557,555555555555555559 %N A178003 Largest n-digit prime with the most digits equal to 5. %C A178003 Select first for the most 5's, then take the largest. %Y A178003 Cf. A037063, A105979, A099659 %K A178003 nonn,base %O A178003 1,1 %A A178003 _Lekraj Beedassy_, May 17 2010