Numbers k such that the string 2,4 occurs in the base 10 representation of k but not of k-1.

Terms

a(0) =24a(1) =124a(2) =224a(3) =240a(4) =324a(5) =424a(6) =524a(7) =624a(8) =724a(9) =824a(10) =924a(11) =1024a(12) =1124a(13) =1224a(14) =1240a(15) =1324a(16) =1424a(17) =1524a(18) =1624a(19) =1724a(20) =1824a(21) =1924a(22) =2024a(23) =2124a(24) =2224a(25) =2240a(26) =2324a(27) =2400a(28) =2524a(29) =2624