Composites with consecutive (ascending) digits.

Terms

a(0) =4a(1) =6a(2) =8a(3) =9a(4) =12a(5) =34a(6) =45a(7) =56a(8) =78a(9) =90a(10) =123a(11) =234a(12) =345a(13) =456a(14) =567a(15) =678a(16) =789a(17) =890a(18) =901a(19) =1234a(20) =2345a(21) =3456a(22) =5678a(23) =6789a(24) =7890a(25) =8901a(26) =9012a(27) =12345a(28) =23456a(29) =34567