OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1000
MATHEMATICA
f[p_, e_] := If[OddQ[e], p, 1]; sqf[n_] := Times @@ (f @@@ FactorInteger[n]); seqQ[n_] := IntegerQ @ DivisorSum[n, 1/sqf[#] &]; Select[Range[2^12], seqQ] (* Amiram Eldar, Apr 02 2020 *)
PROG
(PARI) isok(m) = denominator(sumdiv(m, d, 1/core(d))) == 1; \\ Michel Marcus, Apr 02 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Sep 09 2002
STATUS
approved