Powers of 6 written backwards and sorted.

Terms

a(0) =1a(1) =6a(2) =63a(3) =612a(4) =6777a(5) =6921a(6) =65664a(7) =639972a(8) =6169761a(9) =67166406a(10) =69677001a(11) =650797263a(12) =6332876712a(13) =61049606031a(14) =69046146387a(15) =675489481074