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Least k such that 6*k*prime(n)^2 +1 is prime, where prime(i)=i-th prime.
2

%I #8 Sep 17 2019 10:31:38

%S 3,2,1,3,1,2,2,5,4,2,3,8,2,2,4,7,1,8,3,2,2,1,13,1,2,10,5,3,1,4,2,1,9,

%T 3,5,2,14,3,9,3,3,10,1,5,4,1,2,2,2,6,3,2,1,10,5,7,1,3,10,6,2,7,7,8,5,

%U 3,3,3,2,6,12,1,2,3,12,4,1,3,5,6,2,2,1,3,1,3,3,4,2,14,7,26,9,2,12,3,5,5,7,6

%N Least k such that 6*k*prime(n)^2 +1 is prime, where prime(i)=i-th prime.

%t Table[k = 1; While[ ! PrimeQ[6*k*Prime[n]^2 + 1], k++ ]; k, {n, 100}] (* _Ray Chandler_, Oct 08 2005 *)

%Y Cf. A112744, A112746.

%K nonn

%O 1,1

%A _Pierre CAMI_, Sep 18 2005

%E Extended by _Ray Chandler_, Oct 08 2005