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

Terms

a(0) =11a(1) =60a(2) =77a(3) =109a(4) =158a(5) =207a(6) =256a(7) =305a(8) =354a(9) =403a(10) =420a(11) =452a(12) =501a(13) =539a(14) =599a(15) =648a(16) =697a(17) =746a(18) =763a(19) =795a(20) =844a(21) =893a(22) =942a(23) =991a(24) =1040a(25) =1089a(26) =1106a(27) =1138a(28) =1187a(29) =1236