A023220 Primes p such that 5*p + 8 is also prime.

3, 7, 13, 19, 31, 37, 43, 61, 73, 103, 127, 163, 211, 223, 229, 241, 283, 307, 331, 337, 349, 373, 397, 409, 421, 439, 457, 499, 541, 631, 661, 673, 691, 727, 733, 757, 769, 787, 829, 853, 883, 919, 997, 1021, 1063, 1087, 1123, 1129, 1213, 1231, 1447, 1543, 1549

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Except for the first term all others are congruent to 1 (mod 6) because 5*(6*n+5)+8 is divisible by 3. - Zak Seidov, Aug 23 2012

Links

• John Cerkan, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A002476, A111225 (supersequence).

Programs

Magma

[n: n in [0..1000] | IsPrime(n) and IsPrime(5*n+8)]; // Vincenzo Librandi, Nov 20 2010

Mathematica

Select[Prime[Range[250]],PrimeQ[5#+8]&] (* Harvey P. Dale, Apr 21 2020 *)