Numbers whose base-7 representation is the juxtaposition of two identical strings.

Terms

a(0) =8a(1) =16a(2) =24a(3) =32a(4) =40a(5) =48a(6) =350a(7) =400a(8) =450a(9) =500a(10) =550a(11) =600a(12) =650a(13) =700a(14) =750a(15) =800a(16) =850a(17) =900a(18) =950a(19) =1000a(20) =1050a(21) =1100a(22) =1150a(23) =1200a(24) =1250a(25) =1300a(26) =1350a(27) =1400a(28) =1450a(29) =1500