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A258261
Primes p such that 3p - 4 is also prime.
2
2, 3, 5, 7, 11, 17, 19, 29, 31, 37, 47, 59, 61, 67, 79, 89, 107, 131, 149, 151, 157, 191, 197, 199, 227, 229, 241, 271, 277, 281, 311, 317, 367, 389, 397, 409, 421, 431, 457, 479, 499, 509, 521, 541, 547, 557, 571, 617, 631, 659, 661, 677, 691, 701, 719
OFFSET
1,1
COMMENTS
This sequence is interesting because of the comments in A258233: for n > 1, if 3 * prime(n) - 4 is prime then A258233(n) = 1 + A071704(n), otherwise A258233 (n) = A071704(n). - Zak Seidov, Jun 04 2015
Subsequence of primes of A228121. - Michel Marcus, May 30 2015
EXAMPLE
3 * 2 - 4 = 2, 3 * 3 - 4 = 5, 3 * 5 - 4 = 11, 3 * 7 - 4 = 17, 3 * 11 - 4 = 29 are all prime, so 2, 3, 5, 7, 11 are all in the sequence.
3 * 13 - 4 = 35 = 5 * 7, so 13 is not in the sequence.
MATHEMATICA
Select[Prime[Range[200]], PrimeQ[3# - 4] &]
PROG
(Magma) [p: p in PrimesUpTo(1000) | IsPrime(3*p-4)]; // Vincenzo Librandi, May 25 2015
(PARI) forprime(p=1, 10^3, if(isprime(3*p-4), print1(p, ", "))) \\ Derek Orr, May 27 2015
CROSSREFS
Sequence in context: A280996 A089084 A262835 * A228424 A347192 A335325
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, May 24 2015
STATUS
approved