OFFSET
1,1
COMMENTS
The numbers of terms not exceeding 10^k, for k = 3, 4, ..., are 4, 44, 427, 4264, 42590, 425566, 4255231, 42550413, ... . Apparently, the asymptotic density of this sequence exists and equals 0.00425... . - Amiram Eldar, May 20 2023
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[10000], Abs[Sum[If[d>1&&GCD@@FactorInteger[d][[All, 2]]===1, MoebiusMu[#/d], 0], {d, Divisors[#]}]]>1&]
PROG
(PARI) ok(n)={abs(sumdiv(n, d, if(ispower(d), 0, moebius(n/d)))) > 1} \\ Andrew Howroyd, Aug 26 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 11 2018
STATUS
approved