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 A091318 #9 Sep 21 2012 18:25:08
%S A091318 1,2,1,2,1,1,1,3,2,1,1,1,1,1,2,2,1,1,1,2,1,2,1,2,1,4,1,1,3,2,1,1,1,1,
%T A091318 1,1,2,1,1,3,2,1,4,2,1,1,2,2,3,1,1,3,1,1,1,1,1,2,2,1,1,1,4,1,2,1,1,2,
%U A091318 1,1,2,1,2,1,1,2,2,2,2,1,2,3,2,2,1,1,2,1,2,2,1,2,1,2,1,1,1,2,1,2,2,2,3,3,3
%N A091318 Lengths of runs of 1's in A039702.
%C A091318 Number of primes congruent to 1 mod 4 in sequence before interruption by a prime 3 mod 4.
%D A091318 Enoch Haga, Exploring prime numbers on your PC and the Internet with directions to prime number sites on the Internet, 2001, pages 30-31. ISBN 1-885794-17-7.
%H A091318 T. D. Noe, <a href="/A091318/b091318.txt">Table of n, a(n) for n = 1..10000</a>
%F A091318 Count primes congruent to 1 mod 4 in sequence before interruption by a prime divided by 4 with remainder 3.
%e A091318 a(8)=3 because this is the sequence of primes congruent to 1 mod 4: 89, 97, 101. The next prime is 103, a prime 3 mod 4.
%t A091318 t = Length /@ Split[Table[Mod[Prime[n], 4], {n, 2, 400}]]; Most[Transpose[Partition[t, 2]][[2]]] (* _T. D. Noe_, Sep 21 2012 *)
%Y A091318 Cf. A002144, A002145, A039702, A091267, A091237.
%K A091318 easy,nonn
%O A091318 1,2
%A A091318 _Enoch Haga_, Feb 22 2004