Numbers n such that string 6,6 occurs in the base 10 representation of n but not of n-1.

Terms

a(0) =66a(1) =166a(2) =266a(3) =366a(4) =466a(5) =566a(6) =660a(7) =766a(8) =866a(9) =966a(10) =1066a(11) =1166a(12) =1266a(13) =1366a(14) =1466a(15) =1566a(16) =1660a(17) =1766a(18) =1866a(19) =1966a(20) =2066a(21) =2166a(22) =2266a(23) =2366a(24) =2466a(25) =2566a(26) =2660a(27) =2766a(28) =2866a(29) =2966