Numbers n such that string 7,7 occurs in the base 9 representation of n but not of n+1.

Terms

a(0) =70a(1) =151a(2) =232a(3) =313a(4) =394a(5) =475a(6) =556a(7) =638a(8) =718a(9) =799a(10) =880a(11) =961a(12) =1042a(13) =1123a(14) =1204a(15) =1285a(16) =1367a(17) =1447a(18) =1528a(19) =1609a(20) =1690a(21) =1771a(22) =1852a(23) =1933a(24) =2014a(25) =2096a(26) =2176a(27) =2257a(28) =2338a(29) =2419