a(n) = least positive integer > a(n-1) and not equal to a(i)*a(j)*a(k) for 1<=i<=j<=k<n.

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) =29a(17) =31a(18) =34a(19) =37a(20) =38a(21) =41a(22) =43a(23) =46a(24) =47a(25) =53a(26) =58a(27) =59a(28) =61a(29) =62