OFFSET
1,1
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
EXAMPLE
We see that 225 = 3^2 * 5^2 is not squarefree, and then when starting iterating with A003415, we obtain --> 240 --> 608 --> 1552 --> ... which is a trajectory that will never reach neither a prime nor any squarefree number at all, because already 240 = 2^4 * 3 * 5 is a member of A100716, whose terms all belong into A099309, as any divisor of the form p^p of n will be always present when taking its successive arithmetic derivatives. Thus 225 is included in this sequence.
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 11 2019
STATUS
approved