Central column of triangle A090181.

Terms

a(0) =1a(1) =1a(2) =6a(3) =50a(4) =490a(5) =5292a(6) =60984a(7) =736164a(8) =9202050a(9) =118195220a(10) =1551580888a(11) =20734762776a(12) =281248448936