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 A153434 #2 Mar 30 2012 17:37:48 %S A153434 1,2,2,42,42,1179990,243464796 %N A153434 a(n) is the smallest number m such that all n numbers m+1, m.m+1, ..., m.m. ... .m+1 are prime, where dot means concatenation. %e A153434 All 5 numbers 1+42,1+4242,1+424242,1+42424242 & 1+4242424242 are prime and 42 %e A153434 is the smallest such number so a(5)=42. %Y A153434 Cf. A153435. %K A153434 base,more,nonn %O A153434 1,2 %A A153434 _Farideh Firoozbakht_, Apr 01 2009