Semiprimes with consecutive digits.

Terms

a(0) =4a(1) =6a(2) =9a(3) =10a(4) =21a(5) =34a(6) =65a(7) =87a(8) =123a(9) =321a(10) =543a(11) =789a(12) =901a(13) =1234a(14) =4321a(15) =8765a(16) =34567a(17) =56789a(18) =98765a(19) =654321a(20) =876543a(21) =901234a(22) =1234567a(23) =7654321a(24) =7890123a(25) =10987654a(26) =21098765a(27) =567890123a(28) =12345678901a(29) =54321098765