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

A261538 Primes p such that p^9 + 2 is also prime.

Original entry on oeis.org

11, 41, 101, 227, 461, 587, 641, 887, 977, 1097, 1217, 1559, 2039, 2129, 2357, 3221, 3491, 3677, 3917, 4019, 4547, 5009, 5261, 5279, 5639, 6221, 6359, 6599, 6719, 7187, 7907, 8147, 9767, 9929, 10211, 10391, 11177, 11549, 11801, 11939, 12197, 12671, 13907
Offset: 1

Views

Author

Vincenzo Librandi, Aug 24 2015

Keywords

Comments

All terms == 5 mod 6. Robert Israel, Aug 27 2015

Examples

			11 is in the sequence because 11^9 + 2 = 2357947693 is a prime.

Links

Crossrefs

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

Programs

  • Magma
    [p: p in PrimesUpTo(20000) | IsPrime(p^9+2)];
  • Maple
    select(t -> isprime(t) and isprime(t^9+2), [seq(6*i-1, i=1..10^4)]); # Robert Israel, Aug 27 2015
  • Mathematica
    Select[Prime[Range[2000]], PrimeQ[#^9 + 2] &]
  • PARI
    forprime(p=2, 10^4, if (isprime(p^9+2), print1(p, ", "))) \\ Anders Hellström, Aug 27 2015
  • PARI
    list(lim)=my(v=List(),t); forprime(p=2,lim, if(isprime(p^9+2), listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Aug 27 2015
Showing 1-2 of 2 results.

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

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