%I #12 Jul 28 2015 03:41:14
%S 1,2,1,1,1,1,2523,2,2,1,1,2,1,1,1,2,3,6,63,1,50,38,2,1,1,1,79,1,1,3,1,
%T 4,1,2,2,1,6,1,1,1,5,3,1,18,1,1,11,1,1,26,3,10,1,1,4,2,2,4,1,6,1,4,54,
%U 1,10,1,3,1,2,1,1
%N Least k such that 3*((6*n)^k) - 1 is prime.
%C a(72) > 3830, and the sequence then continues: 6, 2, 7, 1, 27, 2, 3, 1, 7, 2, 1, 1, 4, 36, 346, 1, 1, 1, 1, 3, 6, 2, 1, 2, 444, ...
%C a(72) > 10^4. - _Ray Chandler_, Nov 13 2004
%F a(A138918(n)) = 1. - _Michel Marcus_, Jul 28 2015
%t f[n_] := Block[{k = 1}, While[ !PrimeQ[3*((6*n)^k) - 1], k++ ]; k]; Table[ f[n], {n, 71}] (* _Robert G. Wilson v_, Oct 21 2004 *)
%Y Cf. A098877, A138918.
%K nonn
%O 1,2
%A _Pierre CAMI_, Oct 13 2004
%E Corrected and extended by _Robert G. Wilson v_, Oct 22 2004