18289152domain: NAppears in sequencesa(n) = (2*n+1) * (2*n)! / (sqrt(4*(n+1)*Product_{k=1..2*n+1} lcm(k, 2*n+2-k))).at n=18A082292Triangle read by rows: T(n, k) = binomial(n, k - 1)*(k - 1)^(k - 1)*k*(n - k + 1)^(n - k).at n=43A369019