Odd part of lcm(1,2,3,...,n).

Terms

a(0) =1a(1) =1a(2) =3a(3) =3a(4) =15a(5) =15a(6) =105a(7) =105a(8) =315a(9) =315a(10) =3465a(11) =3465a(12) =45045a(13) =45045a(14) =45045a(15) =45045a(16) =765765a(17) =765765a(18) =14549535a(19) =14549535a(20) =14549535a(21) =14549535a(22) =334639305a(23) =334639305a(24) =1673196525a(25) =1673196525a(26) =5019589575a(27) =5019589575a(28) =145568097675a(29) =145568097675