%I #2 Mar 30 2012 18:39:28
%S 1,2,2,1,3,3,5,7,8,8,8,8,8,8,8,9,11,11,13,15,17,17,19,21,24,22,20,20,
%T 20,18,18,20,18,18,20,19,21,23,23,27,29,31,33,35,35,37,39,43,46,44,44,
%U 42,42,40,40,40,40,38,38,36,36,34,34,35,37,37,39,41,43,43,45,49,51,53,53
%N a(1)=1 then a(n)=(-1)*sum(k=1,n-1,(-1)^a(k)*floor(n/k))
%o (PARI) {an=vector(1000);}{a(n)=if(n<0,0,an[n]);}{an[1]=1;}{for(n=2,1000,an[n]=-sum(k=1,n-1,(-1)^a(k)*floor(n/k))}
%K nonn
%O 1,2
%A _Benoit Cloitre_, Nov 10 2009
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