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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A141544 Odd numbers k such that 2k+5 is a prime.

Original entry on oeis.org

1, 3, 7, 9, 13, 19, 21, 27, 31, 33, 37, 39, 49, 51, 61, 63, 67, 73, 79, 81, 87, 93, 97, 103, 109, 111, 117, 123, 129, 133, 139, 151, 153, 163, 171, 177, 181, 187, 189, 207, 213, 217, 219, 229, 231, 237, 241, 243, 247, 249, 259, 271, 279, 283, 291, 297, 301, 307
Offset: 1

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Author

Giovanni Teofilatto, Aug 16 2008

Keywords

Comments

Superset of A107771. The corresponding primes are given by deleting the first entry in A002145. - R. J. Mathar, Aug 18 2008

Crossrefs

Cf. A002145, A020498, A087915, A089038, A090670, A107771.

Programs

  • Maple
    a:=proc(n) if isprime(2*n+5) then n end if end proc: seq(a(2*n-1), n=1..170); # Emeric Deutsch, Aug 17 2008
  • Mathematica
    Select[Range[1,307,2],PrimeQ[2#+5]&] (* James C. McMahon, Jul 26 2025 *)

Formula

A089038 INTERSECT A005408. - R. J. Mathar, Aug 18 2008
a(n) = A087915(n+1) - 1 = A090670(n+1) - 4. - Giovanni Teofilatto, Sep 07 2008

Extensions

Extended by Emeric Deutsch, Aug 17 2008 and R. J. Mathar, Aug 18 2008
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