Numbers n such that string 9,7 occurs in the base 10 representation of n but not of n-1.

Terms

a(0) =97a(1) =197a(2) =297a(3) =397a(4) =497a(5) =597a(6) =697a(7) =797a(8) =897a(9) =970a(10) =997a(11) =1097a(12) =1197a(13) =1297a(14) =1397a(15) =1497a(16) =1597a(17) =1697a(18) =1797a(19) =1897a(20) =1970a(21) =1997a(22) =2097a(23) =2197a(24) =2297a(25) =2397a(26) =2497a(27) =2597a(28) =2697a(29) =2797