a(1) = 1; a(n+1) = Sum_{k=1..n} lcm(a(k),n)/n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =4a(5) =12a(6) =9a(7) =33a(8) =50a(9) =78a(10) =99a(11) =173a(12) =264a(13) =658a(14) =570a(15) =1056a(16) =1099a(17) =4113a(18) =2443a(19) =10129a(20) =18866a(21) =23226a(22) =39775a(23) =102665a(24) =171529a(25) =256039a(26) =610467a(27) =815809a(28) =1795028a(29) =3854202