A290164 Primes p such that both 4*p - 3 and 3*p - 4 are prime.

2, 5, 11, 19, 29, 59, 61, 79, 89, 131, 149, 151, 191, 389, 431, 479, 499, 521, 541, 571, 631, 659, 701, 739, 919, 941, 971, 1069, 1181, 1279, 1289, 1361, 1381, 1451, 1471, 1489, 1669, 1949, 2069, 2089, 2131, 2549, 2609, 2749, 2791, 3011, 3109, 3181, 3251, 3361

Offset: 1

Author

David James Sycamore, Jul 22 2017

Keywords

• nonn

Comments

For n >= 3, all terms end in 1 or 9. - Robert Israel, Jul 24 2017

Links

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

Crossrefs

Cf. A259730, A290163 (a subsequence).

Programs

Maple

select(p -> isprime(p) and isprime(4*p-3) and isprime(3*p-4), [2,seq(i,i=3..10000,2)]); # Robert Israel, Jul 24 2017

Mathematica

Select[Prime@ Range@ 500, Times @@ Boole@ Map[PrimeQ, {4 # - 3, 3 # - 4}] > 0 &] (* Michael De Vlieger, Jul 23 2017 *)

PARI

forprime(p=2, 10000, if (isprime(3*p-4) && isprime(4*p-3), print1(p, ", "))) \\ Michel Marcus, Jul 23 2017

Extensions

More terms from Michel Marcus, Jul 23 2017