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 1-3 of 3 results.

A242176 Numbers k such that k*6^k + 1 is prime.

Original entry on oeis.org

1, 2, 91, 185, 387, 488, 747, 800, 9901, 10115, 12043, 13118, 30981, 51496
Offset: 1

Views

Author

Vincenzo Librandi, May 08 2014

Keywords

Crossrefs

Cf. numbers n such that n*k^n + 1 is prime: A005849 (k=2), A006552 (k=3), A007646 (k=4), this sequence (k=6), A242177 (k=7), A242178 (k=8), A007647 (k=10), A242196 (k=12), A242197 (k=14), A242198 (k=15), A242199 (k=16), A007648 (k=18).

Programs

  • Magma
    [n: n in [0..1500] | IsPrime(n*6^n+1)];
    
  • Mathematica
    Select[Range[1500], PrimeQ[# 6^# + 1] &]
  • PARI
    is(n)=ispseudoprime(n*6^n+1) \\ Charles R Greathouse IV, Feb 17 2017

Extensions

a(9)-a(14) from Loeh's list (see Links) - Bruno Berselli, May 08 2014

A265013 Numbers n such that n*9^n + 1 is prime.

Original entry on oeis.org

2, 12382, 27608, 31330, 117852
Offset: 1

Views

Author

Tim Johannes Ohrtmann, Nov 30 2015

Keywords

Comments

All terms are even. - Robert Israel, Jan 18 2016

Crossrefs

Programs

  • Magma
    [n: n in [0..100000] | IsPrime(n*9^n+1)];
  • Mathematica
    Select[Range[100000], PrimeQ[# 9^# + 1] &]
  • PARI
    for(n=1,100000, if(isprime(n*9^n+1), print1(n,", ")))
    

A338412 Numbers k such that k * 20^k + 1 is prime.

Original entry on oeis.org

3, 6207, 8076, 22356, 151456
Offset: 1

Views

Author

Tim Johannes Ohrtmann, Oct 25 2020

Keywords

Comments

a(6) > 219976.

Crossrefs

Numbers k such that k * b^k + 1 is prime: A006093 (b=1), A005849 (b=2), A006552 (b=3), A007646 (b=4), A242176 (b=6), A242177 (b=7), A242178 (b=8), A265013 (b=9), A007647(b=10), A242196(b=12), A242197 (b=14), A242198 (b=15), A242199 (b=16), A007648 (b=18), this sequence (b=20).

Programs

  • Magma
    [n: n in [1..10000] |IsPrime(n*20^n+1)]
  • Mathematica
    Select[Range[1, 10000], PrimeQ[n*20^n+1] &]
  • PARI
    for(n=1, 10000, if(isprime(n*20^n+1), print1(n, ", ")))
    
Showing 1-3 of 3 results.