OFFSET
1,6
EXAMPLE
The Zumkeller divisors of 80 are {20, 40, 80}, so a(80) = 64000.
The divisors of 81 are {1, 3, 9, 27, 81}, none of which is Zumkeller, so a(81) = 1.
MAPLE
# The function 'isZumkeller' is defined in A376880.
with(NumberTheory):
zdiv := n -> select(isZumkeller, Divisors(n));
a := n -> mul(k, k in zdiv(n));
seq(a(n), n = 1..80);
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Oct 19 2024
STATUS
approved