A379450 a(n) is the smallest prime p such that omega(p^n - 1) is equal to n, where omega = A001221.

3, 5, 7, 11, 31, 11, 79, 47, 211, 113, 2473, 47, 45841, 389, 1123, 1061

Offset: 1

Author

Juri-Stepan Gerasimov, Dec 23 2024

Keywords

• nonn
• more

Comments

a(17) <= 2487619. - Daniel Suteu, Jan 05 2025

Examples

			a(1) = 3 because omega(3^1 - 1) = omega(2) = 1,
a(2) = 5 because omega(5^2 - 1) = omega(24) = 2,
a(3) = 7 because omega(7^3 - 1) = omega(342) = 3.
		

Crossrefs

Cf. A001221, A219019.

Programs

Mathematica

a[n_] := Module[{p = 2}, While[PrimeNu[p^n - 1] != n, p = NextPrime[p]]; p]; Array[a, 12] (* Amiram Eldar, Dec 25 2024 *)

PARI

a(n) = my(p=2); while (omega(p^n - 1) != n, p=nextprime(p+1)); p; \\ Michel Marcus, Dec 24 2024