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.

A023331 Primes that remain prime through 5 iterations of function f(x) = 2x + 3.

Original entry on oeis.org

47, 67, 1427, 6047, 12097, 16057, 44507, 76537, 92387, 100057, 132707, 209647, 263387, 354247, 407947, 465407, 477727, 507757, 775237, 787477, 788687, 865327, 907367, 955457, 1015517, 1121387, 1178197, 1302277, 1360367, 1524247, 1623707
Offset: 1

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Primes p such that 2*p+3, 4*p+9, 8*p+21, 16*p+45 and 32*p+93 are also prime. - Vincenzo Librandi, Aug 04 2010
Subsequence of A023303. - Michel Marcus, Jun 25 2014

Crossrefs

Cf. A023303 (through 4 iterations).

Programs

  • Magma
    [p: p in PrimesUpTo(2000000) | IsPrime(2*p+3) and IsPrime(4*p+9) and IsPrime(8*p+21) and IsPrime(16*p+45) and IsPrime(32*p+93)]; // Vincenzo Librandi, Aug 04 2010
  • Mathematica
    Select[Prime[Range[20000]], And@@PrimeQ[NestList[2 # + 3 &, #, 5]] &] (* Vincenzo Librandi, Jun 25 2014 *)