A375620 Numbers k such that (20^k - 3^k)/17 is prime.

2, 43, 1723, 2971, 3257, 12263, 38933

Offset: 1

Author

William Dean, Aug 21 2024

Keywords

• hard
• more
• nonn

Comments

All terms must be prime.

a(8) > 10^5.

Examples

			a(1) = 2 corresponds to the prime number 23.
		

Links

• OEIS Wiki, Primes of the form (a^n+b^n)/(a+b) and (a^n-b^n)/(a-b)

Crossrefs

Cf. A028491, A057468, A128032, A059801, A121877, A128024, A128025, A128026, A128027, A128028, A128029, A128030, A128031, A128032.

Programs

PARI

is(k) = ispseudoprime((20^k - 3^k)/17)