a(n) = least positive integer > a(n-1) and not a(i)*a(j) for 1<=i<=j<=n, n >= 2.

Terms

a(0) =1a(1) =3a(2) =4a(3) =5a(4) =6a(5) =7a(6) =8a(7) =10a(8) =11a(9) =13a(10) =14a(11) =17a(12) =19a(13) =22a(14) =23a(15) =26a(16) =27a(17) =29a(18) =31a(19) =34a(20) =37a(21) =38a(22) =41a(23) =43a(24) =45a(25) =46a(26) =47a(27) =53a(28) =54a(29) =58