

A158318


Primes p such that 5p2 is prime.


6



3, 5, 11, 17, 23, 47, 53, 59, 71, 89, 101, 113, 131, 137, 149, 173, 191, 197, 233, 239, 257, 311, 317, 347, 383, 401, 431, 443, 449, 467, 479, 509, 569, 593, 617, 641, 683, 719, 761, 773, 827, 857, 929, 941, 947, 1031, 1061, 1097, 1163, 1181, 1223, 1229
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OFFSET

1,1


COMMENTS

Hence 5p are terms in A157931, A062721 and (except of 25) in A043326.


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000


MATHEMATICA

Select[Prime[Range[300]], PrimeQ[5#2]&] (* Harvey P. Dale, Apr 10 2015 *)


PROG

(PARI) isok(p) = isprime(p) && isprime(5*p2); \\ Michel Marcus, Oct 16 2013


CROSSREFS

Cf. A043326 Numbers n such that n is a product of two different primes and n2 is prime, A062721 Numbers n such that n is a product of two primes and n2 is prime, A157931 Numbers that are both the sum and the product of two primes.
Sequence in context: A106902 A293711 A155938 * A099596 A200748 A063693
Adjacent sequences: A158315 A158316 A158317 * A158319 A158320 A158321


KEYWORD

nonn


AUTHOR

Zak Seidov, Mar 16 2009


STATUS

approved



