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

Terms

a(0) =1a(1) =3a(2) =11a(3) =25a(4) =137a(5) =147a(6) =1089a(7) =2283a(8) =7129a(9) =7381a(10) =83711a(11) =86021a(12) =1145993a(13) =1171733a(14) =1195757a(15) =2436559a(16) =42142223a(17) =42822903a(18) =825887397a(19) =837527025a(20) =848612385a(21) =859193865a(22) =19994251455a(23) =20217344325a(24) =102157567401a(25) =103187226801a(26) =312536252003a(27) =315404588903