T(n,n-1), array T as in A054090.

Terms

a(0) =1a(1) =2a(2) =2a(3) =8a(4) =24a(5) =106a(6) =546a(7) =3368a(8) =24032a(9) =195170a(10) =1777650a(11) =17950552a(12) =199059672a(13) =2405063018a(14) =31448531954a(15) =442501797656