Numbers n such that string 6,6 occurs in the base 7 representation of n but not of n+1.

Terms

a(0) =48a(1) =97a(2) =146a(3) =195a(4) =244a(5) =293a(6) =342a(7) =391a(8) =440a(9) =489a(10) =538a(11) =587a(12) =636a(13) =685a(14) =734a(15) =783a(16) =832a(17) =881a(18) =930a(19) =979a(20) =1028a(21) =1077a(22) =1126a(23) =1175a(24) =1224a(25) =1273a(26) =1322a(27) =1371a(28) =1420a(29) =1469