Distinct terms in A307616.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =12a(5) =60a(6) =120a(7) =360a(8) =840a(9) =2520a(10) =27720a(11) =55440a(12) =360360a(13) =720720a(14) =12252240a(15) =232792560a(16) =1163962800a(17) =3491888400a(18) =5354228880