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A127505 Triangle T(n,k) = mobius(n/k)*phi(k) if k|n, otherwise T(n,k)=0; 1<=k<=n.

%I A127505 #6 Mar 30 2012 17:25:15
%S A127505 1,-1,1,-1,0,2,0,-1,0,2,-1,0,0,0,4,1,-1,-2,0,0,2,-1,0,0,0,0,0,6,0,0,0,
%T A127505 -2,0,0,0,4,0,0,-2,0,0,0,0,0,6,1,-1,0,0,-4,0,0,0,0,4,-1,0,0,0,0,0,0,0,
%U A127505 0,0,10,0,1,0,-2,0,-2,0,0
%N A127505 Triangle T(n,k) = mobius(n/k)*phi(k) if k|n, otherwise T(n,k)=0; 1<=k<=n.
%F A127505 T(n,k) = sum_{j=k..n} A054525(n,j)*A130207(j,k), 1<=k<=n.
%e A127505 First few rows of the triangle are:
%e A127505 1;
%e A127505 -1, 1;
%e A127505 -1, 0, 2;
%e A127505 0, -1, 0, 2;
%e A127505 -1, 0, 0, 0, 4;
%e A127505 1, -1, -2, 0, 0, 2;
%e A127505 ...
%Y A127505 Cf. A051731, A000010 (diagonal n=k), A007431 (row sums), A008683 (column k=1).
%K A127505 easy,tabl,sign
%O A127505 1,6
%A A127505 _Gary W. Adamson_, Jan 17 2007