A236688 Primes p such that prime(p^2) + 2 is also prime.

7, 53, 83, 107, 149, 223, 367, 509, 701, 769, 853, 971, 1039, 1229, 1283, 1327, 1373, 1381, 1439, 1447, 1459, 1783, 1873, 1973, 2237, 2243, 2269, 2339, 2347, 2437, 2459, 2521, 2531, 2797, 2857, 3001, 3391, 3413, 3461, 3583, 3593, 3631, 3659, 3769, 3889, 3947

Offset

1,1

Links

K. D. Bajpai, Table of n, a(n) for n = 1..1119

Example

7 is prime and appears in the sequence: prime(7^2) = 227 and 227+2 = 229, which is also prime.
53 is prime and appears in the sequence: prime(53^2) = 25469 and 25469+2 = 25471, which is also prime.

Maple

KD := proc() local a, b; a:=ithprime(n); b:=ithprime(a^2)+2; if isprime (b) then RETURN (a); fi; end: seq(KD(), n=1..700);

Mathematica

Select[Prime[Range[600]], PrimeQ[Prime[#^2]+2]&] (* Harvey P. Dale, Aug 29 2021 *)

Prog

(PARI)
default(primelimit, 2^31)
s=[]; forprime(p=2, 4000, if(isprime(prime(p^2)+2), s=concat(s, p))); s \\ Colin Barker, Jan 30 2014

Crossrefs

Cf. A000040, A234695, A236119.

Sequence in context: A357362 A224501 A241487 * A239941 A253123 A352459

Adjacent sequences: A236685 A236686 A236687 * A236689 A236690 A236691

Keyword

nonn

Author

K. D. Bajpai, Jan 29 2014

Status

approved