Xenodromes: all digits in base 5 are different.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =7a(7) =8a(8) =9a(9) =10a(10) =11a(11) =13a(12) =14a(13) =15a(14) =16a(15) =17a(16) =19a(17) =20a(18) =21a(19) =22a(20) =23a(21) =27a(22) =28a(23) =29a(24) =35a(25) =38a(26) =39a(27) =40a(28) =42a(29) =44