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.

Showing 1-3 of 3 results.

A153222 Duplicate of A023222.

Original entry on oeis.org

2, 5, 11, 17, 29, 31, 37, 61, 67, 71, 89, 101, 109, 127, 137, 167
Offset: 1

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Author

Keywords

A023258 Primes that remain prime through 2 iterations of function f(x) = 6x + 7.

Original entry on oeis.org

5, 17, 29, 37, 89, 127, 199, 229, 269, 347, 359, 379, 397, 499, 769, 809, 929, 947, 977, 1049, 1087, 1129, 1277, 1279, 1367, 1409, 1439, 1489, 1499, 1607, 1609, 1787, 2017, 2039, 2089, 2399, 2539, 2707, 2819, 2837, 2957, 3089, 3109, 3217, 3229, 3389, 3499
Offset: 1

Views

Author

David W. Wilson

Keywords

Comments

Primes p such that 6*p+7 and 36*p+49 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

Crossrefs

Subsequence of A023222, A153218. - John Cerkan, Sep 14 2016

Programs

  • Magma
    [n: n in [1..100000] | IsPrime(n) and IsPrime(6*n+7) and IsPrime(36*n+49)] // Vincenzo Librandi, Aug 04 2010
  • Mathematica
    nrpQ[n_]:=AllTrue[Rest[NestList[6#+7&,n,2]],PrimeQ]; Select[Prime[ Range[ 500]],nrpQ] (* Harvey P. Dale, Oct 12 2020 *)

Formula

a(n) = 7 or 9 (mod 10) for n > 1. - John Cerkan, Sep 14 2016

A023289 Primes that remain prime through 3 iterations of function f(x) = 6x + 7.

Original entry on oeis.org

5, 37, 127, 347, 977, 2017, 3607, 5477, 9137, 10487, 13687, 14057, 14107, 19037, 19697, 19727, 20507, 22157, 23887, 24097, 25237, 25307, 26717, 26777, 27107, 29347, 30697, 33757, 33997, 34667, 34847, 35117, 35227, 37057, 40577, 40627, 41177, 41597
Offset: 1

Views

Author

David W. Wilson

Keywords

Comments

Primes p such that 6*p+7, 36*p+49 and 216*p+301 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

Crossrefs

Subsequence of A023222, A023258, and A153218.

Programs

  • Magma
    [n: n in [1..150000] | IsPrime(n) and IsPrime(6*n+7) and IsPrime(36*n+49) and IsPrime(216*n+301)] // Vincenzo Librandi, Aug 04 2010

Formula

a(n) == 7 (mod 10), for n > 1. - John Cerkan, Sep 21 2016
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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