%I #6 Apr 09 2014 10:16:34
%S 3,1,3,0,1,1,0,1,2,0,1,0,0,1,2,0,0,3,0,1,1,0,1,0,0,1,0,0,1,1,0,0,1,0,
%T 1,1,0,0,2,0,1,0,0,1,0,0,0,2,0,1,1,0,1,1,0,1,0,0,0,0,0,0,1,0,1,0,0,1,
%U 2,0,0,0,0,1,1,0,0,2,0,0,1,0,1,0,0,1,0,0,1,1,0,0,0,0,1,1,0,1,2,0,0,0,0,0,3
%N a(n) is the largest nonnegative integer m such that 2*n*k+1 is prime for all k where 1<=k<=m. a(n) = 0 if 2n+1 is composite.
%e For n = 3: 2*3*1 +1 = 7, which is prime. 2*3*2 + 1 = 13, which is prime. 2*3*3 + 1 = 19, which is prime. But 2*3*4 + 1 = 25, which is composite. So a(3) = 3, because there are 3 primes in the arithmetic sequence before hitting a composite.
%Y A146525
%K nonn
%O 1,1
%A _Leroy Quet_, Oct 30 2008
%E Extended by _Ray Chandler_, Nov 01 2008