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 A138149 #8 Jan 25 2013 12:24:46
%S A138149 1,1,0,0,0,1,1,1,1,1,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,
%T A138149 0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,
%U A138149 0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
%N A138149 n-th run has length n-th prime, with values 0 and 1 only, starting with 1.
%e A138149 .n ..... Run ....................... Length
%e A138149 .1 ..... 1,1 ....................... 2
%e A138149 .2 ..... 0,0,0 ..................... 3
%e A138149 .3 ..... 1,1,1,1,1 ................. 5
%e A138149 .4 ..... 0,0,0,0,0,0,0 ............. 7
%e A138149 .5 ..... 1,1,1,1,1,1,1,1,1,1,1 ..... 11
%t A138149 Flatten[Table[{Table[1,{Prime[n]}],Table[0,{Prime[n+1]}]},{n,1,11,2}]] (* _Harvey P. Dale_, Jan 25 2013 *)
%Y A138149 Cf. A000040, A057211.
%K A138149 easy,nonn
%O A138149 1,1
%A A138149 _Omar E. Pol_, Mar 29 2008