a(n) = lcm({i + 1, i = 0..n}) / Product_{d | n, d + 1 prime} d.

Terms

a(0) =1a(1) =1a(2) =1a(3) =6a(4) =2a(5) =30a(6) =10a(7) =420a(8) =84a(9) =1260a(10) =420a(11) =13860a(12) =132a(13) =180180a(14) =60060a(15) =360360a(16) =24024a(17) =6126120a(18) =291720a(19) =116396280a(20) =705432a(21) =116396280a(22) =38798760a(23) =2677114440a(24) =9806280a(25) =13385572200a(26) =13385572200a(27) =40156716600a(28) =2677114440a(30) =5041319400