46587905domain: NAppears in sequencesTriangle read by rows: T(n,k) = T(n-1,k-1) + k^2*T(n-1,k), 1 < k <= n, T(n,1) = 1.at n=49A036969a(n) = [x^n] Product_{k=1..n} 1/(1-k^2*x).at n=5A298851Expansion of 1/((1-x) * (1-4*x) * (1-9*x) * (1-16*x) * (1-25*x)).at n=5A383840