A023234 Primes p such that 9*p + 4 is also prime.

3, 7, 11, 17, 23, 31, 37, 41, 67, 71, 73, 83, 97, 107, 113, 137, 163, 191, 193, 197, 223, 263, 283, 307, 311, 317, 337, 353, 367, 373, 401, 421, 461, 491, 577, 601, 613, 617, 631, 643, 647, 653, 661, 683, 727, 743, 751, 773, 797, 821, 823, 853, 857, 881, 883, 907, 947

Offset: 1

Author

David W. Wilson

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..2000

Programs

Magma

[n: n in [0..1000] | IsPrime(n) and IsPrime(9*n+4)]; // Vincenzo Librandi, Nov 20 2010

Mathematica

Select[Prime[Range[1000]], PrimeQ[9 # + 4]&] (* Vincenzo Librandi, Feb 02 2014 *)