OFFSET
1,1
COMMENTS
d is a Zumkeller divisor of n if and only if d is a divisor of n and is Zumkeller (A083207).
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..10000
FORMULA
If d is the only Zumkeller divisor of n and n is Zumkeller then d = n.
MAPLE
# The function 'isZumkeller' is defined in A376880.
zdiv := n -> select(isZumkeller, NumberTheory:-Divisors(n)):
select(n -> nops(zdiv(n)) = 1, [seq(1..4000)]);
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Oct 19 2024
STATUS
approved