a(n) = lcm({1, 2, ..., n}) * (n + 1) / n for n > 0, a(0) = 1.

Terms

a(0) =1a(1) =2a(2) =3a(3) =8a(4) =15a(5) =72a(6) =70a(7) =480a(8) =945a(9) =2800a(10) =2772a(11) =30240a(12) =30030a(13) =388080a(14) =386100a(15) =384384a(16) =765765a(17) =12972960a(18) =12932920a(19) =245044800a(20) =244432188a(21) =243877920a(22) =243374040a(23) =5587021440a(24) =5577321750a(25) =27841990176a(26) =27800803800a(27) =83288004800a(28) =83181770100