a(n+1) = a(n)/n if n|a(n) else a(n)*n, a(1) = 1.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =120a(6) =20a(7) =140a(8) =1120a(9) =10080a(10) =1008a(11) =11088a(12) =924a(13) =12012a(14) =858a(15) =12870a(16) =205920a(17) =3500640a(18) =194480a(19) =3695120a(20) =184756a(21) =3879876a(22) =176358a(23) =4056234a(24) =97349616a(25) =2433740400a(26) =93605400a(27) =2527345800a(28) =90262350a(29) =2617608150