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 A154520 #6 Jul 16 2015 21:48:45
%S A154520 1,4,8,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,5,5,5,5,6,6,7,7,7,7,7,8,9,9,9,9,
%T A154520 0,1,1,1,1,1,1,1,2,1,2,1,1,1,3,1,3,4,1,4,4,4,5,1,1,5,1,6,1,6,1,7,1,1,
%U A154520 8,1,8,8,1,1,1,0,0,2,0,2,1,2,1,2,2,2,2,2,3,2,3,3,2,4,2,4,4,5,2,2,2,6,7,7,2
%N A154520 The prime(n)-th digit of the concatenated nonprimes.
%C A154520 The concatenated nonprimes A141468 are A129808 with an initial 0.
%F A154520 a(n) = A129808(prime(n)-1) .
%p A154520 a129808 := [1] : for n from 4 to 400 do if not isprime(n) then a129808 := [op(a129808), op(ListTools[Reverse](convert(n,base,10))) ] ; fi; od:
%p A154520 for n from 1 do p := ithprime(n) ; printf("%d,", op(p-1,a129808) ) ; od: # _R. J. Mathar_, Aug 03 2009
%Y A154520 Cf. A000040, A141468.
%K A154520 nonn,base
%O A154520 1,2
%A A154520 _Juri-Stepan Gerasimov_, Jan 11 2009
%E A154520 Edited and extended by _R. J. Mathar_, Aug 03 2009