OFFSET
1,1
MATHEMATICA
r[n_] := EulerPhi[n]/MultiplicativeOrder[2, n]; d[n_] := DivisorSum[n, r[#] &]; f[n_] := (m = MultiplicativeOrder[2, n])*d[n] - m + 1; MultiplicativeOrder[2, #] & /@ Select[Range[10^5], CompositeQ[#] && Total@(r /@ Divisors[#]) - 1 == 3 &] (* Amiram Eldar, Sep 12 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Jun 15 2008
EXTENSIONS
a(4) corrected and more terms added by Amiram Eldar, Sep 12 2019
STATUS
approved