Near-repunit semiprimes.

Terms

a(0) =115a(1) =118a(2) =119a(3) =121a(4) =141a(5) =161a(6) =411a(7) =511a(8) =611a(9) =1011a(10) =1101a(11) =1114a(12) =1115a(13) =1119a(14) =1121a(15) =1141a(16) =1191a(17) =1211a(18) =1411a(19) =1711a(20) =5111a(21) =7111a(22) =9111a(23) =11101a(24) =11114a(25) =11141a(26) =11181a(27) =11611a(28) =11911a(29) =13111