A092104 Primes of form p*q + 4, with prime p and q.

13, 19, 29, 37, 43, 53, 59, 61, 73, 89, 97, 127, 137, 149, 163, 173, 181, 191, 223, 239, 241, 251, 257, 263, 269, 271, 293, 307, 313, 331, 359, 397, 419, 421, 431, 449, 457, 509, 521, 523, 541, 547, 557, 563, 569, 577, 587, 593, 601, 653, 659, 673, 683, 691

Offset: 1

Author

Zak Seidov, Feb 20 2004

Keywords

• easy
• nonn

Comments

Primes of form p*q + 2, A063638. Primes common in A063638 and A092104, A092105. Primes of form p*p + 4, A045637.

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A045637, A063638, A092105.

Programs

Mathematica

With[{upto=700},Select[Times@@#+4&/@Tuples[Prime[Range[PrimePi[upto/2]]], 2], PrimeQ[#]&&#<+upto&]]//Union (* Harvey P. Dale, Jul 23 2016 *)

PARI

list(lim)=my(v=List(),t); forprime(p=3,(lim-4)\3, forprime(q=3,min((lim-4)\p, p), t=p*q+4; if(isprime(t), listput(v,t)))); Set(v) \\ Charles R Greathouse IV, Aug 05 2016