

A236688


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


5



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
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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);


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: A301485 A224501 A241487 * A239941 A253123 A141911
Adjacent sequences: A236685 A236686 A236687 * A236689 A236690 A236691


KEYWORD

nonn


AUTHOR

K. D. Bajpai, Jan 29 2014


STATUS

approved



