OFFSET
1,9
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
EXAMPLE
For n=70, its divisors are {1, 2, 5, 7, 10, 14, 35, 70} and their first differences are {1, 3, 2, 3, 4, 21, 35}, of which the differences {3, 3, 4, 21} are not divisors, so a(70) = 4. Note that in contrast to A060763, here the difference 3 is counted twice because there are two copies of it among the differences.
PROG
(PARI) A360118(n) = { my(d=divisors(n), erot = vector(#d-1, k, d[k+1] - d[k])); sum(i=1, #erot, !!(n%erot[i])); };
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 20 2023
STATUS
approved