Numbers n such that string 2,5 occurs in the base 10 representation of n but not of n-1.

Terms

a(0) =25a(1) =125a(2) =225a(3) =250a(4) =325a(5) =425a(6) =525a(7) =625a(8) =725a(9) =825a(10) =925a(11) =1025a(12) =1125a(13) =1225a(14) =1250a(15) =1325a(16) =1425a(17) =1525a(18) =1625a(19) =1725a(20) =1825a(21) =1925a(22) =2025a(23) =2125a(24) =2225a(25) =2250a(26) =2325a(27) =2425a(28) =2500a(29) =2625