A250027 Primes p such that f(p) and f(f(p)) are primes, where f(x) = x^2+3*x+1.

3, 19, 29, 59, 113, 373, 379, 419, 449, 593, 643, 929, 983, 1063, 1423, 2053, 2069, 3169, 3593, 3943, 4159, 4493, 5153, 6163, 6659, 6689, 6869, 6949, 7583, 8963, 9629, 10099, 10103, 12413, 13963, 14303, 14639, 15359, 15649, 16703, 17099, 18523, 18869

Offset

1,1

Links

Zak Seidov, Table of n, a(n) for n = 1..1000

Mathematica

Select[Range[25000], PrimeQ[#] && PrimeQ[#^2 + 3 # + 1] && PrimeQ[#^4 + 6 #^3 + 14 #^2 + 15 # + 5] &] (* Vincenzo Librandi, Nov 19 2014 *)

Prog

(Magma) f:=func<i | i^2+3*i+1>; [p: p in PrimesUpTo(22000) | IsPrime(f(p)) and IsPrime(f(f(p)))]; // Vincenzo Librandi, Nov 19 2014

Crossrefs

Subsequence of A094210 and of A153590.

Sequence in context: A339864 A180451 A108137 * A339545 A102978 A218537

Adjacent sequences: A250024 A250025 A250026 * A250028 A250029 A250030

Keyword

nonn

Author

Zak Seidov, Nov 11 2014

Status

approved