A240618 Primes p such that p*q*r + 2 is prime, where q and r are the next two primes after p.

3, 13, 257, 307, 409, 431, 587, 719, 733, 1031, 1109, 1123, 1129, 1237, 1657, 1987, 1999, 2143, 2179, 2239, 2411, 2467, 2843, 3041, 3191, 3433, 3691, 3943, 4051, 4219, 4289, 4561, 4567, 4721, 4817, 4831, 4943, 4993, 5521, 5563, 5623, 5689, 5813, 6257, 6983, 7043

Offset

1,1

Comments

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

Links

K. D. Bajpai, Table of n, a(n) for n = 1..6606

Maple

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);

Mathematica

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

Crossrefs

Cf. A000040, A048880, A051507, A240596.

Sequence in context: A015701 A220294 A006487 * A042823 A132560 A128385

Adjacent sequences: A240615 A240616 A240617 * A240619 A240620 A240621

Keyword

nonn

Author

K. D. Bajpai, Apr 09 2014

Status

approved