OFFSET
1,2
COMMENTS
Subset of A020477.
EXAMPLE
Divisors of 102 are 1, 2, 3, 6, 17, 34, 51, 102 and their sum is 216 = 6^3.
MAPLE
with(numtheory): P:=proc(q) local a, k, n;
for n from 1 to q do a:=sort([op(divisors(n))]);
for k from 1 to nops(a) do if sigma(n)=a[k]^3 then print(n); break; fi; od; od; end: P(10^9);
MATHEMATICA
Select[Range[10^6], Mod[#, DivisorSigma[1, #]^(1/3)] == 0 &] (* Michael De Vlieger, May 06 2018 *)
PROG
(PARI) isok(n) = (n==1) || (ispower(s=sigma(n), 3) && !(n % sqrtnint(s, 3))); \\ Michel Marcus, May 05 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paolo P. Lava, May 04 2018
STATUS
approved