If d,e are consecutive digits of n in base 7, then |d-e|>=5.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =6a(6) =13a(7) =35a(8) =42a(9) =43a(10) =91a(11) =92a(12) =250a(13) =251a(14) =299a(15) =300a(16) =307a(17) =642a(18) =643a(19) =650a(20) =1750a(21) =1757a(22) =1758a(23) =2093a(24) =2100a(25) =2101a(26) =2149a(27) =2150a(28) =4494a(29) =4501