A352630 First of two consecutive primes p,q such that either p+2*q and (2*p+q)/5 or (p+2*q)/5 and 2*p+q are primes.

7, 11, 17, 19, 101, 109, 227, 229, 277, 349, 521, 743, 769, 839, 937, 983, 1151, 1373, 1427, 1609, 1721, 1823, 2039, 2081, 2267, 2273, 2843, 3373, 3433, 3779, 3821, 3847, 3967, 4217, 4517, 4583, 5417, 5531, 5669, 5779, 6197, 6577, 6701, 6761, 6883, 7537, 7669, 7727, 8467, 8609, 8837, 9173, 9281

Offset: 1

Author

J. M. Bergot and Robert Israel, Mar 24 2022

Keywords

• nonn

Examples

			a(3) = 17 is a term because it is prime, the next prime is 19, and (17+2*19)/5 = 11 and 2*17+19 = 53 are prime.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A181848.

Programs

Maple

R:= NULL: q:= 2:
while q < 10000 do
  p:= q; q:= nextprime(p); s:= p+2*q; t:= 2*p+q;
  if (s mod 5 = 0 and isprime(s/5) and isprime(t)) or (t mod 5 = 0 and isprime(s) and isprime(t/5)) then R:= R,p;
  fi
od:
R;