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