Numbers k such that the string 6,6 occurs in the base 9 representation of k but not of k-1.

Terms

a(0) =60a(1) =141a(2) =222a(3) =303a(4) =384a(5) =465a(6) =540a(7) =627a(8) =708a(9) =789a(10) =870a(11) =951a(12) =1032a(13) =1113a(14) =1194a(15) =1269a(16) =1356a(17) =1437a(18) =1518a(19) =1599a(20) =1680a(21) =1761a(22) =1842a(23) =1923a(24) =1998a(25) =2085a(26) =2166a(27) =2247a(28) =2328a(29) =2409