Numbers n such that string 7,0 occurs in the base 10 representation of n but not of n-1.

Terms

a(0) =70a(1) =170a(2) =270a(3) =370a(4) =470a(5) =570a(6) =670a(7) =700a(8) =770a(9) =870a(10) =970a(11) =1070a(12) =1170a(13) =1270a(14) =1370a(15) =1470a(16) =1570a(17) =1670a(18) =1700a(19) =1770a(20) =1870a(21) =1970a(22) =2070a(23) =2170a(24) =2270a(25) =2370a(26) =2470a(27) =2570a(28) =2670a(29) =2700