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%I #27 Oct 09 2017 02:17:52
%S 1,1,1,0,1,0,1,0,0,0,1,-1,1,0,0,0,1,-1,1,0,0,0,1,-1,0,0,0,0,1,-2,1,0,
%T 0,0,0,0,1,0,0,-1,1,0,1,0,-1,0,1,0,0,-1,0,0,1,0,0,-1,0,0,1,-1,1,0,-1,
%U 0,0,0,1,0,0,-2,1,0,1,0,-1,0,0,0,1,-1,0,0,1,-1,0,0,0,0,1,-1,0,0,0,0,0,0,1,-1,0,0,1,0,1
%N a(n) = Sum_{k|n, k<=sqrt(n)} mu(k) where mu(k) is the Moebius function and the sum is over the positive divisors k of n with k <= sqrt(n).
%H Reinhard Zumkeller, <a href="/A068101/b068101.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = Sum_{k=1..A038548(n)} A008683(A161906(n,k)). - _Reinhard Zumkeller_, Jul 30 2013
%F G.f.: Sum_{k>=1} mu(k)*x^(k^2)/(1 - x^k). - _Ilya Gutkovskiy_, Jan 03 2017
%t Table[DivisorSum[n, MoebiusMu, # <= Sqrt[n] &], {n, 103}] (* _Michael De Vlieger_, Sep 24 2017 *)
%o (Haskell)
%o a068101 = sum . map a008683 . a161906_row
%o -- _Reinhard Zumkeller_, Jul 30 2013
%o (PARI) a(n) = sumdiv(n, k, (k<=sqrt(n))*moebius(k)); \\ _Michel Marcus_, Jan 03 2017
%Y Cf. A086956.
%K sign
%O 1,30
%A _Leroy Quet_, Mar 22 2002
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