Leading diagonal of A111467.

Terms

a(0) =1a(1) =3a(2) =14a(3) =56a(4) =280a(5) =1872a(6) =11760a(7) =104832a(8) =1224720a(9) =12545280a(10) =96526080a(11) =1163289600a(12) =13891046400a(13) =200222668800