a(n) = LCM(1,2,...,n) / n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =12a(5) =10a(6) =60a(7) =105a(8) =280a(9) =252a(10) =2520a(11) =2310a(12) =27720a(13) =25740a(14) =24024a(15) =45045a(16) =720720a(17) =680680a(18) =12252240a(19) =11639628a(20) =11085360a(21) =10581480a(22) =232792560a(23) =223092870a(24) =1070845776a(25) =1029659400a(26) =2974571600a(27) =2868336900a(28) =80313433200a(29) =77636318760