A342717 Primes q such that 15*q-4, 15*q-2, 15*q+2 and 15*q+4 are all primes.

7, 13, 139, 1049, 4481, 8147, 11047, 11411, 13049, 17191, 17921, 25913, 26321, 28057, 30169, 33349, 37561, 38177, 40487, 42139, 60493, 65563, 72871, 74507, 74521, 77041, 77069, 93491, 112363, 127849, 130621, 138389, 142787, 144577, 145109, 158227, 161561, 165311

Offset: 1

Author

Tamas Nagy, Mar 19 2021

Keywords

• nonn

Comments

The 4 generated primes always end with 1, 3, 7, 9 in base 10 in this order.

Examples

			a(1) = 7 is a term since 7 is prime and 101, 103, 107, 109 are also prime.
Some larger examples include:
  171850185252132304529579363573540628229,
  204480960976715817535460959250816270267,
  338006806817314508391110932058603239271.
		

Programs

Mathematica

Select[Prime@ Range[10^4], AllTrue[Flatten[#1 + {-#2, #2}], PrimeQ] & @@ {15 #, {2, 4}} &] (* Michael De Vlieger, Mar 19 2021 *)

PARI

isok(p) = isprime(p) && isprime(15*p-4) && isprime(15*p-2) && isprime(15*p+2) && isprime(15*p+4);