cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A258261 Primes p such that 3p - 4 is also prime.

Original entry on oeis.org

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

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Author

Zak Seidov, May 24 2015

Keywords

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

Examples

			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.
		

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(1000) | IsPrime(3*p-4)]; // Vincenzo Librandi, May 25 2015
    
  • Mathematica
    Select[Prime[Range[200]], PrimeQ[3# - 4] &]
  • PARI
    forprime(p=1,10^3,if(isprime(3*p-4),print1(p,", "))) \\ Derek Orr, May 27 2015