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 A280418 #4 Jan 02 2017 17:31:58 %S A280418 0,2,9,11,27,29,95,97,121,151,152,215,216,1613,1614,2341,2342,5483, %T A280418 5484,18061,18062,29401,29402 %N A280418 Length of shortest prefix of the characteristic sequence of the primes A010051 that contains all possible length-n blocks appearing in that sequence. %e A280418 For n = 2 the prefix 011010100 of length 9 contains all 4 blocks, and it is the shortest such prefix. %Y A280418 Cf. A010051, A280417. %K A280418 nonn,more %O A280418 0,2 %A A280418 _Jeffrey Shallit_, Jan 02 2017