a(n) = Product_{k|n} (n+1-k).

Terms

a(0) =1a(1) =2a(2) =3a(3) =12a(4) =5a(5) =120a(6) =7a(7) =280a(8) =63a(9) =540a(10) =11a(11) =83160a(12) =13a(13) =1456a(14) =2145a(15) =28080a(16) =17a(17) =636480a(18) =19a(19) =1136960a(20) =5985a(21) =5544a(22) =23a(23) =1070845776a(24) =525a(25) =9100a(26) =12825a(27) =6237000a(28) =29a(29) =5320224000