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

Terms

a(0) =1a(1) =2a(2) =4a(3) =5a(4) =6a(5) =7a(6) =8a(7) =25a(8) =26a(9) =33a(10) =36a(11) =37a(12) =43a(13) =44a(14) =45a(15) =46a(16) =47a(17) =49a(18) =50a(19) =52a(20) =62a(21) =65a(22) =66a(23) =69a(24) =72a(25) =77a(26) =237a(27) =289a(28) =309a(29) =317