41983200domain: NAppears in sequencesa(n) is the number of sets of natural numbers [a,b,c,d,e] that can be produced with the numbers [0..n] such that the values of all the distinct parenthesized expressions of a-b-c-d-e are different.at n=34A054026a(n) = Product_{k=1..L} hypergeom([-n, -n], [1], k) with L = 4.at n=3A301393