Numbers with the property that all pairs of consecutive base-4 digits differ by 0 or 1.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =6a(6) =9a(7) =10a(8) =11a(9) =14a(10) =15a(11) =16a(12) =17a(13) =20a(14) =21a(15) =22a(16) =25a(17) =26a(18) =27a(19) =36a(20) =37a(21) =38a(22) =41a(23) =42a(24) =43a(25) =46a(26) =47a(27) =57a(28) =58a(29) =59