Numbers n such that string 4,0 occurs in the base 10 representation of n but not of n+1.

Terms

a(0) =40a(1) =140a(2) =240a(3) =340a(4) =409a(5) =440a(6) =540a(7) =640a(8) =740a(9) =840a(10) =940a(11) =1040a(12) =1140a(13) =1240a(14) =1340a(15) =1409a(16) =1440a(17) =1540a(18) =1640a(19) =1740a(20) =1840a(21) =1940a(22) =2040a(23) =2140a(24) =2240a(25) =2340a(26) =2409a(27) =2440a(28) =2540a(29) =2640