Duplicate of A072513.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =4a(5) =60a(6) =6a(7) =168a(8) =48a(9) =360a(10) =10a(11) =47520a(12) =12a(13) =1092a(14) =1680a(15) =20160a(16) =16a(17) =440640a(18) =18