Smallest positive multiple of n whose base-4 representation contains only 0's and 1's.

Terms

a(0) =1a(1) =4a(2) =21a(3) =4a(4) =5a(5) =84a(6) =21a(7) =16a(8) =81a(9) =20a(10) =341a(11) =84a(12) =65a(13) =84a(14) =1365a(15) =16a(16) =17a(17) =324a(18) =1045a(19) =20a(20) =21a(21) =1364a(22) =69a(23) =336a(24) =325a(25) =260a(26) =81a(27) =84a(28) =261a(29) =5460