%I #8 Apr 11 2014 18:33:41

%S 3,13,257,307,409,431,587,719,733,1031,1109,1123,1129,1237,1657,1987,

%T 1999,2143,2179,2239,2411,2467,2843,3041,3191,3433,3691,3943,4051,

%U 4219,4289,4561,4567,4721,4817,4831,4943,4993,5521,5563,5623,5689,5813,6257,6983,7043

%N Primes p such that p*q*r + 2 is prime, where q and r are the next two primes after p.

%C All the terms in the sequence, except a(1), are congruent to 1 mod 6.

%H K. D. Bajpai, <a href="/A240618/b240618.txt">Table of n, a(n) for n = 1..6606</a>

%p KD := proc(n) local a,b; a:=ithprime(n)*ithprime(n+1)*ithprime(n+2); b:=a+2; if isprime(b) then RETURN (ithprime(n)); fi; end: seq(KD(n), n=1..2000);

%t KD={}; Do[p=Prime[n]; If[PrimeQ[p*Prime[n+1]*Prime[n+2] + 2], AppendTo[KD,p]], {n,1000}]; KD

%Y Cf. A000040, A048880, A051507, A240596.

%K nonn

%O 1,1

%A _K. D. Bajpai_, Apr 09 2014