Katadromes: digits in base 5 are in strict descending order.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =10a(7) =11a(8) =15a(9) =16a(10) =17a(11) =20a(12) =21a(13) =22a(14) =23a(15) =55a(16) =80a(17) =85a(18) =86a(19) =105a(20) =110a(21) =111a(22) =115a(23) =116a(24) =117a(25) =430a(26) =555a(27) =580a(28) =585a(29) =586