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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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified September 22 12:34 EDT 2020. Contains 337289 sequences. (Running on oeis4.)