Numbers whose base-4 digits are in nonincreasing order.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =8a(6) =9a(7) =10a(8) =12a(9) =13a(10) =14a(11) =15a(12) =16a(13) =20a(14) =21a(15) =32a(16) =36a(17) =37a(18) =40a(19) =41a(20) =42a(21) =48a(22) =52a(23) =53a(24) =56a(25) =57a(26) =58a(27) =60a(28) =61a(29) =62