a(n) = least positive integer > a(n-1) and not a(i)*a(j)+2 for 1<=i<j<=n, with initial terms 1,3.

Terms

a(0) =1a(1) =3a(2) =4a(3) =7a(4) =8a(5) =11a(6) =12a(7) =15a(8) =16a(9) =19a(10) =20a(11) =24a(12) =25a(13) =28a(14) =29a(15) =32a(16) =33a(17) =36a(18) =37a(19) =40a(20) =41a(21) =44a(22) =45a(23) =48a(24) =49a(25) =52a(26) =53a(27) =56a(28) =57a(29) =60