%I
%S 1,2,2,1,2,1,2,2,2,2,1,1,2,1,1,4,1,1,1,1,1,2,1,1,2,2,1,1,2,7,1,1,1,1,
%T 1,1,1,2,2,1,2,2,3,1,1,2,1,2,5,1,2,2,1,1,1,1,1,2,1,1,1,2,1,1,1,1,2,1,
%U 3,1,1,1,2,3,2,2,5,5,1,1,1,2,1,1,1,1,2,4,2,1,1,1,1,2,3,1,1,1,2,2,1,1,3,4,1
%N Lengths of runs of 3's in A039702.
%C Number of primes congruent to 3 mod 4 in sequence before interruption by a prime 1 mod 4.
%D Enoch Haga, Exploring prime numbers on your PC and the Internet with directions to prime number sites on the Internet, 2001, pages 3031. ISBN 1885794177.
%H T. D. Noe, <a href="/A091267/b091267.txt">Table of n, a(n) for n = 1..10000</a>
%F Count primes congruent to 3 mod 4 in sequence before interruption by a prime divided by 4 with remainder 1.
%e a(16)=4 because this is the sequence of primes congruent to 3 mod 4: 199, 211, 223, 227. The next prime is 229, a prime 1 mod 4.
%t t = Length /@ Split[Table[Mod[Prime[n], 4], {n, 2, 400}]]; Most[Transpose[Partition[t, 2]][[1]]] (* _T. D. Noe_, Sep 21 2012 *)
%Y Cf. A002144, A002145, A091318, A039702, A091237.
%K easy,nonn
%O 1,2
%A _Enoch Haga_, Feb 22 2004
