OFFSET
1,3
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..20000
FORMULA
EXAMPLE
For n = 17, the iteration proceeds as follows 17 -> 18 (= 2*3*3), 18 -> 13 (13 is a prime), 13 -> 14 (= 2*7), 14 -> 8 (= 2*2*2), 8 -> 1. The largest prime factor present after the initial step is 13, thus a(17) = 13.
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Aug 28 2021
STATUS
approved