T(n,n-6), array T as in A038738.

Terms

a(0) =1a(1) =15a(2) =122a(3) =715a(4) =3388a(5) =13817a(6) =50439a(7) =169324a(8) =533115a(9) =1597981a(10) =4613544a(11) =12948083a(12) =35582783a(13) =96296410a(14) =257763847a(15) =684721291a(16) =1809437921a(17) =4765066652a(18) =12520359325a(19) =32850638623a(20) =86116228859a(21) =225627072434