n!/A124900(n).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =6a(5) =10a(6) =120a(7) =35a(8) =280a(9) =4536a(10) =362880a(11) =5775a(12) =39916800a(13) =24710400a(14) =8408400a(15) =2627625a(17) =2858856000a(19) =15277011750