a(n) = floor(lcm(1,2,...n)/(1+2+...+n)).

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =4a(5) =2a(6) =15a(7) =23a(8) =56a(9) =45a(10) =420a(11) =355a(12) =3960a(13) =3432a(14) =3003a(15) =5299a(16) =80080a(17) =71650a(18) =1225224a(19) =1108536a(20) =1007760a(21) =920128a(22) =19399380a(23) =17847429a(24) =82372752a(25) =76271066a(26) =212469400a(27) =197816337a(28) =5354228880a(29) =5008794758