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.

A219283 Primes of the form 13^k - 12^k.

Original entry on oeis.org

6431804812640900941, 31211427601852046808999765129652549, 4519079836942618423019040742735616921552429101, 22137406298265966315641393147750228275603823278911109
Offset: 1

Views

Author

Vincenzo Librandi, Nov 23 2012

Keywords

Crossrefs

Cf. A062579 (associated k).

Programs

  • Magma
    [a: n in [0..200] | IsPrime(a) where a is  13^n - 12^n];
  • Mathematica
    Select[Table[13^n - 12^n, {n, 0, 200}], PrimeQ]

A286348 Numbers n such that 4^n + (-3)^n is prime.

Original entry on oeis.org

0, 3, 4, 7, 16, 17, 59, 283, 311, 383, 499, 521, 541, 599, 1193, 1993, 2671, 7547, 24019, 46301, 48121, 68597, 91283, 131497, 148663, 184463, 341233
Offset: 1

Views

Author

Juri-Stepan Gerasimov, May 07 2017

Keywords

Comments

Numbers n such that (1 + k)^n + (-k)^n is prime:
0 (k = 0);
A285929 (k = 1);
A283653 (k = 2);
this sequence (k = 3);
0, 2, 3, 4, 43, 59, 191, 223, ... (k = 4);
0, 2, 5, 8, 11, 13, 16, 23, 61, 83, ...(k = 5);
0, 3, 4, 7, 16, 29, 41, 67, ... (k = 6);
0, 2, 7, 11, 16, 17, 29, 31, 79, 43, 131, 139, ... (k = 7);
0, 4, 7, 29, 31, 32, 67, ... (k = 8);
0, 2, 3, 4, 7, 11, 19, 29, ... (k = 9);
0, 3, 5, 19, 32, ... (k = 10);
0, 3, 7, 89, 101, ... (k = 11);
0, 2, 4, 17, 31, 32, 41, 47, 109, 163, ... (k = 12);
0, 3, 4, 11, 83, ... (k = 13);
0, 2, 3, 4, 16, 43, 173, 193, ... (k = 14);
0, 43, ... (k = 15);
0, 4, 5, 7, 79, ... (k = 16);
0, 2, 3, 8, 13, 71, ... (k = 17);
0, 1607, ... (k = 18);
...
Primes of the form (1 + n)^(2^n) + n: 5, 83, 65539, 7958661109946400884391941, ...
Numbers m such that (1 + k)^m + (-k)^m is not odd prime for k =< m: 0, 1, 15, 18, 53, 59, 106, 114, 124, 132, 133, 143, 177, 214, 232, 234, 240, 256, ...
Conjecture: if (1 + y)^x + (-y)^x is a prime number then x is zero, or an even power of two, or an odd prime number.

Examples

			3 is in this sequence because 4^3 + (-3)^3 = 37 is prime.
4 is in this sequence because 4^4 + (-3)^4 = 337 is prime.
		

Crossrefs

Programs

  • Magma
    [n: n in [0..250] | IsPrime(4^n+(-3)^n)];
    
  • Mathematica
    Select[Range[0, 3000], PrimeQ[4^# + (-3)^#] &] (* Michael De Vlieger, May 09 2017 *)
  • PARI
    is(n)=ispseudoprime(4^n+(-3)^n) \\ Charles R Greathouse IV, Jun 13 2017
Showing 1-2 of 2 results.