OFFSET
0
COMMENTS
Characteristic function of A099309.
LINKS
FORMULA
a(n) = 1 if n is in A100716 or ends there by repeated applications of A003415, otherwise a(n) = 0 (when n instead reaches 0 by such iteration).
For all n, a(n) >= A341996(n).
For all n > 0, a(n) = [A256750(n) < 1].
For all n > 1, a(n) >= [A341997(n) > 1].
a(n) = 1 - A328308(n), and for n >= 1, a(n) = A342023(n) + A359546(n). - Antti Karttunen, Jan 05 2023
PROG
(PARI)
A003415checked(n) = if(n<=1, 0, my(f=factor(n), s=0); for(i=1, #f~, if(f[i, 2]>=f[i, 1], return(0), s += f[i, 2]/f[i, 1])); (n*s));
A341999(n) = if(!n, n, while(n>1, n = A003415checked(n)); (!n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 28 2021
STATUS
approved