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%I #24 Aug 12 2021 05:04:00
%S -1,0,1,0,1,0,1,0,0,0,1,0,1,0,-1,0,1,0,1,0,-1,0,1,0,0,0,0,0,1,0,1,0,
%T -1,0,-1,0,1,0,-1,0,1,0,1,0,0,0,1,0,0,0,-1,0,1,0,-1,0,-1,0,1,0,1,0,0,
%U 0,-1,0,1,0,-1,0,1,0,1,0,0,0,-1,0,1,0,0,0,1,0,-1,0,-1,0,1,0,-1,0,-1,0,-1,0,1,0,0,0,1,0,1,0,1
%N a(n) = Moebius(2n).
%C b(n) = -a(n) is multiplicative with b(2^e) = 0, b(p) = -1 if p >= 3, 0 otherwise. - _David W. Wilson_, Jun 12 2005
%H Antti Karttunen, <a href="/A099991/b099991.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A008683(2n). - _Wesley Ivan Hurt_, Dec 17 2013
%p with(numtheory); A099991:=n->mobius(2*n); seq(A099991(n), n=1..100); # _Wesley Ivan Hurt_, Dec 17 2013
%t MoebiusMu[2*Range[110]] (* _Harvey P. Dale_, Jul 13 2012 *)
%o (PARI) A099991(n) = moebius(2*n); \\ _Antti Karttunen_, Sep 14 2017
%Y Bisection of A008683. Cf. A099990.
%K sign,easy
%O 1,1
%A _N. J. A. Sloane_, Nov 20 2004