A378832 Numbers k such that 5^k + 68 is prime.

1, 3, 7, 133, 331, 453, 10365

Offset: 1

Author

Robert Price, Dec 08 2024

Keywords

• nonn
• hard
• more

Comments

a(8) > 22000. - Matthew L. LaSelle, Feb 25 2025

a(8) > 100000. - Michael S. Branicky, Mar 28 2025

Examples

			3 is a term because 5^3 + 68 = 193 is prime.
		

Crossrefs

Cf. A089142, A124621, A217133.

Programs

Magma

[k: k in [0..1000] |IsPrime (5^k+68)];

Mathematica

Select[Range[0,5000],PrimeQ[5^#+68]&]

Extensions

a(7) from Michael S. Branicky, Dec 17 2024