a(1)=1; for n > 0, a(n+1) = rad(a(n))*n where rad=A007947.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =30a(6) =180a(7) =210a(8) =1680a(9) =1890a(10) =2100a(11) =2310a(12) =27720a(13) =30030a(14) =420420a(15) =450450a(16) =480480a(17) =510510a(18) =9189180a(19) =9699690a(20) =193993800a(21) =203693490a(22) =213393180a(23) =223092870a(24) =5354228880a(25) =5577321750a(26) =5800414620a(27) =6023507490a(28) =6246600360a(29) =6469693230