Semiprimes with strictly increasing product of digits.

Terms

a(0) =4a(1) =6a(2) =9a(3) =25a(4) =26a(5) =35a(6) =38a(7) =39a(8) =49a(9) =58a(10) =69a(11) =87a(12) =249a(13) =259a(14) =278a(15) =289a(16) =299a(17) =398a(18) =478a(19) =489a(20) =579a(21) =589a(22) =679a(23) =689a(24) =699a(25) =789a(26) =799a(27) =889a(28) =899a(29) =2589