a(n) is the number of triangular arrays containing the first 3*(n - 1) positive integers arranged with number n on each side and having different set of the sets of the side integers.

A351223

a(n) is the number of triangular arrays containing the first 3*(n - 1) positive integers arranged with number n on each side and having different set of the sets of the side integers.

Terms

    a(0) =1a(1) =120a(2) =7560a(3) =369600a(4) =15765750a(5) =617512896a(6) =22813670880a(7) =807723671040

External references