A370157 Primes p such that both 3p+2 and (p-2)/3 are composite or 0.

2, 31, 47, 61, 67, 73, 101, 107, 109, 137, 151, 157, 181, 191, 193, 211, 223, 229, 241, 263, 271, 277, 281, 283, 307, 331, 347, 359, 373, 379, 389, 401, 421, 431, 443, 461, 463, 467, 487, 509, 541, 547, 557, 563, 571, 587, 601, 613, 617, 619, 631, 641, 647

Offset: 1

Author

Clark Kimberling, Feb 10 2024

Keywords

• nonn

Crossrefs

Cf. A000040, A115058 (supersequence), A023208, A370156.

Programs

Mathematica

Select[Prime[Range[200]], ! PrimeQ[3 # + 2] && ! PrimeQ[(# - 2)/3] &]

PARI

isok(p) = if (isprime(p), !isprime(3*p+2) && !(((p%3) == 2) && isprime((p-2)/3))); \\ Michel Marcus, Feb 17 2024