Numbers whose base-7 representation contains exactly four 6's.

Terms

a(0) =2400a(1) =4801a(2) =7202a(3) =9603a(4) =12004a(5) =14405a(6) =14748a(7) =15091a(8) =15434a(9) =15777a(10) =16120a(11) =16463a(12) =16512a(13) =16561a(14) =16610a(15) =16659a(16) =16708a(17) =16757a(18) =16764a(19) =16771a(20) =16778a(21) =16785a(22) =16792a(23) =16799a(24) =16800a(25) =16801a(26) =16802a(27) =16803a(28) =16804a(29) =16805