Every base 4 digit of k is a base 7 digit of k.

Terms

a(0) =1a(1) =2a(2) =3a(3) =9a(4) =52a(5) =84a(6) =85a(7) =86a(8) =87a(9) =105a(10) =106a(11) =170a(12) =191a(13) =255a(14) =345a(15) =352a(16) =357a(17) =358a(18) =360a(19) =361a(20) =362a(21) =366a(22) =368a(23) =369a(24) =381a(25) =394a(26) =406a(27) =409a(28) =410a(29) =415