a(n) = lcm{1, 2, ..., n}/(n*(n-1)), n >= 2.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =2a(5) =10a(6) =15a(7) =35a(8) =28a(9) =252a(10) =210a(11) =2310a(12) =1980a(13) =1716a(14) =3003a(15) =45045a(16) =40040a(17) =680680a(18) =612612a(19) =554268a(20) =503880a(21) =10581480a(22) =9699690a(23) =44618574a(24) =41186376a(25) =114406600a(26) =106234700a(27) =2868336900a(28) =2677114440a(29) =77636318760