Numbers whose base-7 representation contains exactly four 5's.

Terms

a(0) =2000a(1) =4401a(2) =6802a(3) =9203a(4) =11604a(5) =12290a(6) =12633a(7) =12976a(8) =13319a(9) =13662a(10) =13760a(11) =13809a(12) =13858a(13) =13907a(14) =13956a(15) =13970a(16) =13977a(17) =13984a(18) =13991a(19) =13998a(20) =14000a(21) =14001a(22) =14002a(23) =14003a(24) =14004a(25) =14006a(26) =14012a(27) =14054a(28) =14348a(29) =16406