A237423 Primes p such that prime(prime(p^2)) - 2 is also prime.

13, 17, 167, 179, 211, 223, 337, 373, 541, 661, 743, 751, 1063, 1129, 1217, 1607, 1697, 1741, 1913, 2017, 2039, 2083, 2293, 2389, 2447, 2459, 2543, 2677, 2693, 2711, 2851, 2909, 3083, 3191, 3209, 3259, 3571, 3889, 3917

Offset

1,1

Links

K. D. Bajpai, Table of n, a(n) for n = 1..155

Example

13 is prime and appears in the sequence because  prime(prime(13^2)) - 2  = 8009 which is also prime.
17 is prime and appears in the sequence because  prime(prime(17^2)) - 2  = 16139 which is also prime.

Maple

KD := proc() local a, b;  a:=ithprime(n);  b:=ithprime(ithprime(a^2))-2;  if isprime (b) then RETURN (a); fi;  end: seq(KD(), n=1..500);

Mathematica

p[n_] := PrimeQ[Prime[Prime[n^2]] - 2]; n = 0; Do[If[p[Prime[m]], n = n + 1; Print[n, " ", Prime[m]]], {m, 1000}] (* Bajpai *)
Select[Prime[Range[105]], PrimeQ[Prime[Prime[#^2]] - 2] &] (* Wouter Meeussen, Feb 09 2014 *)

Crossrefs

Cf. A000040, A234695, A236119, A236687, A236688, A237283

Sequence in context: A202136 A123909 A176555 * A342725 A292003 A257373

Adjacent sequences: A237420 A237421 A237422 * A237424 A237425 A237426

Keyword

nonn,base,less

Author

K. D. Bajpai, Feb 07 2014

Status

approved