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.

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A023342 Primes that remain prime through 5 iterations of function f(x) = 5x + 4.

Original entry on oeis.org

5333, 26669, 294167, 324869, 344189, 578297, 676829, 807407, 894893, 1078559, 1114427, 1174487, 1624349, 1883363, 2247923, 2926769, 3075029, 3196871, 3427871, 3558407, 4037039, 4205879, 5392799, 6130823, 6479423, 6714497, 6750113, 6915299
Offset: 1

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Comments

Primes p such that 5*p+4, 25*p+24, 125*p+124, 625*p+624 and 3125*p+3124 are also primes. - Vincenzo Librandi, Aug 05 2010

Crossrefs

Subsequence of A023218, A023253, A023284, A023314, and A024897.

Programs

  • Magma
    [n: n in [1..10000000] | IsPrime(n) and IsPrime(5*n+4) and IsPrime(25*n+24) and IsPrime(125*n+124) and IsPrime(625*n+624) and IsPrime(3125*n+3124)] // Vincenzo Librandi, Aug 05 2010
  • Mathematica
    Select[Prime[Range[500000]],AllTrue[Rest[NestList[5#+4&,#,5]],PrimeQ]&] (* Harvey P. Dale, Jan 01 2022 *)

Formula

a(n) == 41 (mod 42). - John Cerkan, Oct 20 2016
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