A392052 Numbers k such that (24^k - 5^k)/19 is prime.

2, 5, 7, 17, 47, 1549, 5393, 5483, 6397, 11329, 46301

Offset

1,1

Comments

The definition implies that k must be a prime.

a(12) > 10^5.

Links

Table of n, a(n) for n=1..11.

P. Bourdelais, A Generalized Repunit Conjecture.

J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.

H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7.

H. Lifchitz, Mersenne and Fermat primes field

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

Eric Weisstein's World of Mathematics, Repunit.

Mathematica

Select[Prime[Range[10000]], PrimeQ[(24^# - 5^#)/19] &]

Crossrefs

Cf. A062587, A062589, A127996, A127997, A128344, A204940, A217320, A225807, A229542, A375161, A375236, A377031.

Sequence in context: A303677 A303802 A045357 * A168035 A247323 A099357

Adjacent sequences: A392049 A392050 A392051 * A392053 A392054 A392055

Keyword

nonn,hard,more,changed

Author

Robert Price, Jan 26 2026

Status

approved