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.

A261537 Primes p such that p^7 + 2 is also prime.

Original entry on oeis.org

53, 449, 521, 653, 881, 983, 1031, 1451, 1571, 1733, 1889, 2129, 2729, 3191, 4259, 5879, 6173, 7499, 7829, 8861, 9743, 9923, 10271, 10313, 11423, 11903, 12041, 12149, 12263, 12329, 12641, 12893, 14591, 14723, 14771, 14813, 15401, 16493, 17783, 18713, 19259
Offset: 1

Views

Author

Vincenzo Librandi, Aug 24 2015

Keywords

Comments

Subsequence of primes of A216980. - Michel Marcus, Aug 24 2015

Examples

			53^7 + 2 = 1174711139839 is a prime.

Crossrefs

Cf. A000040, A216980.
Subsequence of A007528.
Cf. similar sequences listed in A261536.

Programs

  • Magma
    [p: p in PrimesUpTo(20000) | IsPrime(p^7+2)];
  • Maple
    A261537:=n->`if`(isprime(n) and isprime(n^7+2), n, NULL): seq(A261537(n), n=1..5*10^4); # Wesley Ivan Hurt, Apr 14 2017
  • Mathematica
    Select[Prime[Range[2500]], PrimeQ[#^7 + 2] &]
  • PARI
    first(m)=my(v=vector(m));i=1;for(j=1,m,while(!isprime((prime(i)^7)+2),i++);v[j]=prime(i);i++);v; \\ Anders Hellström, Aug 24 2015

A216981 Primes of the form n^7+2.

Original entry on oeis.org

2, 3, 4782971, 1801088543, 1174711139839, 3938980639169, 93206534790701, 425927596977749, 1107984764452583, 2149422977421877, 7416552901015627, 19891027786401119, 307732862434921877, 830512886046548069, 1042842864990234377, 3678954248903875651
Offset: 1

Views

Author

Michel Lagneau, Sep 21 2012

Keywords

Links

Crossrefs

Cf. A056899, A144953, A216975, A216977, A216979.

Programs

  • Magma
    [a: n in [0..500] | IsPrime(a) where a is n^7+2]; // Vincenzo Librandi, Mar 15 2013
  • Mathematica
    lst={}; Do[p=n^7+2; If[PrimeQ[p], AppendTo[lst, p]], {n, 6!}]; lst
Select[Table[n^7 + 2, {n, 0, 400}], PrimeQ] (* Vincenzo Librandi, Mar 15 2013 *)
  • PARI
    v=select(n->isprime(n^7+2),vector(2000,n,n-1)); /* A216980 */
vector(#v, n, v[n]^7+2)
/* Joerg Arndt, Sep 21 2012 */
  • PARI
    select(isprime, vector(2000,n,(n-1)^7+2)) \\ Charles R Greathouse IV, Sep 21 2012
Showing 1-2 of 2 results.

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