OFFSET
1,1
COMMENTS
Tested up to n = 10^6.
EXAMPLE
Anti-divisors of 54 are 4, 12, 36. Their sum is 52.
Again, anti-divisors of 52 are 3, 5, 7, 8, 15, 21, 35. Their sum is 94.
Finally, anti-divisors of 94 are 3, 4, 7, 9, 11, 17, 21, 27, 63. Their sum is 162 and 162 / 54 = 3.
MAPLE
with(numtheory); P:=proc(q, h) local a, i, j, k, n;
for n from 4 to q do a:=n; for i from 1 to h do
k:=0; j:=a; while j mod 2 <> 1 do k:=k+1; j:=j/2; od;
a:=sigma(2*a+1)+sigma(2*a-1)+sigma(a/2^k)*2^(k+1)-6*a-2; od;
if type(a/n, integer) then print(n); fi; od; end: P(10^6, 3);
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Paolo P. Lava, Oct 01 2013
EXTENSIONS
Offset corrected and a(26)-a(32) from Donovan Johnson, Jan 09 2014
STATUS
approved