OFFSET

1,4

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..630

EXAMPLE

a(8)=3 because Pell(8)=408 has prime factors {2, 2, 2, 3, 17}.

MATHEMATICA

PrimeNu[LinearRecurrence[{2, 1}, {1, 2}, 85]] (* Amiram Eldar, Oct 21 2023 *)

CROSSREFS

KEYWORD

nonn

AUTHOR

Tyler Busby, Oct 21 2023

STATUS

approved