OFFSET
1,1
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..655 (terms < 10^13; first 155 terms from Amiram Eldar and Robert G. Wilson v)
MATHEMATICA
fQ[n_] := CoprimeQ[n*DivisorSigma[0, n], DivisorSigma[1, n]] && !IntegerQ@ Sqrt@ n && !IntegerQ@ Log2@ n; Select[Range[10^6], fQ@# &]
PROG
(Magma) [k:k in [1..10000000]|Gcd(k*NumberOfDivisors(k), DivisorSigma(1, k)) eq 1 and (not IsSquare(k)) and (not IsIntegral(Log(2, k)))]; // Marius A. Burtea, Dec 23 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar and Robert G. Wilson v, Dec 22 2019
STATUS
approved