44806domain: NAppears in sequencesTriangle read by rows: T(n,k) = 3*T(n-1,k-1) + 3*T(n-1,k) - 2*T(n-2,k-1) with T(n,0) = T(n,n) = 1.at n=40A152613a(n) = Sum_{k=1..n} (k * floor(n/k))^3.at n=15A356249