a(n) = product of prohibited prime factors of A090252(n).

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =15a(5) =30a(6) =70a(7) =210a(8) =462a(9) =6006a(10) =51051a(11) =102102a(12) =277134a(13) =6374082a(14) =10623470a(15) =223092870a(16) =588153930a(17) =18232771830a(18) =51893273670