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A026598
Sum{T(i,j)}, 0<=j<=i, 0<=i<=n, T given by A026584.
Conjecture: n*a(n) +(-4*n+3)*a(n-1) +(-2*n+3)*a(n-2) +5*(4*n-9)*a(n-3) +7*(-n+3)*a(n-4) +6*(-4*n+15)*a(n-5) +8*(2*n-9)*a(n-6)=0. - R. J. Mathar, Jun 23 2013