Numbers whose base-7 representation contains exactly four 0's.

Terms

a(0) =2401a(1) =4802a(2) =7203a(3) =9604a(4) =12005a(5) =14406a(6) =16808a(7) =16809a(8) =16810a(9) =16811a(10) =16812a(11) =16813a(12) =16814a(13) =16821a(14) =16828a(15) =16835a(16) =16842a(17) =16849a(18) =16856a(19) =16905a(20) =16954a(21) =17003a(22) =17052a(23) =17101a(24) =17150a(25) =17493a(26) =17836a(27) =18179a(28) =18522a(29) =18865