A092186(n)/2.

Terms

a(0) =1a(1) =1a(2) =4a(3) =6a(4) =36a(5) =72a(6) =576a(7) =1440a(8) =14400a(9) =43200a(10) =518400a(11) =1814400a(12) =25401600a(13) =101606400a(14) =1625702400a(15) =7315660800a(16) =131681894400a(17) =658409472000