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 A093338 #3 Oct 01 2013 17:57:59
%S A093338 2,3,5,7,2,2,3,3,5,5,7,7,7,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,
%T A093338 3,3,3,3,3,3,3,3,3,3,3,5,5,5,5,5,5,5,5,5,5,5,5,5,5,7,7,7,7,7,7,7,7,7,
%U A093338 7,7,7,7,7,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2
%N A093338 Scan primes, write down initial digit if it is a prime.
%o A093338 (PARI) firstpr(n) = { forprime(x=2,n, fd = eval(mid(Str(x),1,1)); if(isprime(fd),print1(fd",")) ) } \ Get a substring of length n from string str starting at position s in str. mid(str,s,n) = { v =""; tmp = Vec(str); ln=length(tmp); for(x=s,s+n-1, v=concat(v,tmp[x]); ); return(v) }
%Y A093338 Cf. A077648.
%K A093338 base,nonn
%O A093338 2,1
%A A093338 _Cino Hilliard_, Apr 25 2004