

A240618


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


1



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
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OFFSET

1,1


COMMENTS

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


LINKS



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



KEYWORD

nonn


AUTHOR



STATUS

approved



