A diagonal of triangle in A008298.

Terms

a(0) =1a(1) =9a(2) =59a(3) =450a(4) =3394a(5) =30912a(6) =293292a(7) =3032208a(8) =36290736a(9) =433762560a(10) =5925016800a(11) =83648747520