Numbers with digits 6 and 8 only.

Terms

a(0) =6a(1) =8a(2) =66a(3) =68a(4) =86a(5) =88a(6) =666a(7) =668a(8) =686a(9) =688a(10) =866a(11) =868a(12) =886a(13) =888a(14) =6666a(15) =6668a(16) =6686a(17) =6688a(18) =6866a(19) =6868a(20) =6886a(21) =6888a(22) =8666a(23) =8668a(24) =8686a(25) =8688a(26) =8866a(27) =8868a(28) =8886a(29) =8888