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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A303740 Primes of the form 9*k^2 + 3*k + 1.

Original entry on oeis.org

13, 43, 157, 241, 463, 601, 757, 1123, 2971, 3307, 4423, 4831, 5701, 6163, 8191, 9901, 11131, 12433, 13807, 19183, 20023, 21757, 22651, 23563, 26407, 28393, 35911, 37057, 53593, 60763, 78121, 83233, 95791, 113233, 117307, 121453, 123553, 127807, 136531, 143263
Offset: 1

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Author

Muniru A Asiru, Jun 01 2018

Keywords

Crossrefs

Cf. A303739.
Subsequence of A082040.

Programs

  • GAP
    Filtered(List([0..300],n->9*n^2+3*n+1),IsPrime);
    
  • Magma
    [a: n in [0..200] | IsPrime(a) where a is 9*n^2 +3*n+1 ];// Vincenzo Librandi, Jun 25 2018
  • Maple
    select(isprime,[seq(9*n^2+3*n+1,n=0..500)]);
  • Mathematica
    Select[Table[9 n^2 + 3 n + 1, {n, 0, 150}], PrimeQ] (* Vincenzo Librandi, Jun 25 2018 *)

Formula

a(n) = A082040(A303739(n)). - Elmo R. Oliveira, May 04 2025
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