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 1-2 of 2 results.

A301811 Primes of form 3*k^k + 2.

Original entry on oeis.org

5, 83, 9377, 2470631
Offset: 1

Views

Author

Seiichi Manyama, Mar 27 2018

Keywords

Comments

The next term is too large to include.
This sequence is different from A216146.

Crossrefs

Primes of form b*k^k + b - 1: A216148 (b=2), this sequence (b=3), A301808 (b=4).
Cf. A160360, A301644.

Formula

a(n) = 3*A160360(n+1)^A160360(n+1) + 2.

A228613 Least prime factor of (2n+1)^(2n+1)+2.

Original entry on oeis.org

3, 29, 53, 3, 59, 97, 3, 23, 7, 3, 31, 19, 3, 5, 51131, 3, 5, 2003, 3, 229, 139, 3, 4215399123059, 5, 3, 179, 5, 3, 43, 7, 3, 103993, 61141, 3, 19961719, 13, 3, 2391083871204802979, 331, 3, 89, 30707, 3, 5, 601, 3, 5
Offset: 0

Views

Author

M. F. Hasler and Stanislav Sykora, Feb 22 2014

Keywords

Comments

Suggested by S. Sykora in a discussion in the OEIS users group on LinkedIn, since the numbers to be factored here are more "elementary" than those of the existing A216146, in turn motivated by A160360.
As of today, a(47) seems not yet known.

Links

Crossrefs

Cf. A216146, A160360.

Programs

  • Mathematica
    Table[FactorInteger [((2 n + 1)^(2 n + 1) + 2)][[1, 1]], {n, 0, 46}] (* Vincenzo Librandi, Feb 24 2014 *)
FactorInteger[#^#+2][[1,1]]&/@Range[1,91,2] (* Harvey P. Dale, Aug 27 2023 *)
  • PARI
    A228613=n->factor((2*n+1)^(2*n+1)+2)[1,1]

Formula

a(3k)=3 for all k >= 0.
Showing 1-2 of 2 results.

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