Numbers k such that string 1,9 occurs in the base 10 representation of k but not of k-1.

Terms

a(0) =19a(1) =119a(2) =190a(3) =219a(4) =319a(5) =419a(6) =519a(7) =619a(8) =719a(9) =819a(10) =919a(11) =1019a(12) =1119a(13) =1190a(14) =1219a(15) =1319a(16) =1419a(17) =1519a(18) =1619a(19) =1719a(20) =1819a(21) =1900a(22) =2019a(23) =2119a(24) =2190a(25) =2219a(26) =2319a(27) =2419a(28) =2519a(29) =2619