Numbers in base 7.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =6a(7) =10a(8) =11a(9) =12a(10) =13a(11) =14a(12) =15a(13) =16a(14) =20a(15) =21a(16) =22a(17) =23a(18) =24a(19) =25a(20) =26a(21) =30a(22) =31a(23) =32a(24) =33a(25) =34a(26) =35a(27) =36a(28) =40a(29) =41