Numbers n such that string 7,5 occurs in the base 10 representation of n but not of n-1.

Terms

a(0) =75a(1) =175a(2) =275a(3) =375a(4) =475a(5) =575a(6) =675a(7) =750a(8) =775a(9) =875a(10) =975a(11) =1075a(12) =1175a(13) =1275a(14) =1375a(15) =1475a(16) =1575a(17) =1675a(18) =1750a(19) =1775a(20) =1875a(21) =1975a(22) =2075a(23) =2175a(24) =2275a(25) =2375a(26) =2475a(27) =2575a(28) =2675a(29) =2750