Numbers n such that string 4,7 occurs in the base 10 representation of n but not of n-1.

Terms

a(0) =47a(1) =147a(2) =247a(3) =347a(4) =447a(5) =470a(6) =547a(7) =647a(8) =747a(9) =847a(10) =947a(11) =1047a(12) =1147a(13) =1247a(14) =1347a(15) =1447a(16) =1470a(17) =1547a(18) =1647a(19) =1747a(20) =1847a(21) =1947a(22) =2047a(23) =2147a(24) =2247a(25) =2347a(26) =2447a(27) =2470a(28) =2547a(29) =2647