Katadromes: digits in base 11 are in strict descending order.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =6a(7) =7a(8) =8a(9) =9a(10) =10a(11) =11a(12) =22a(13) =23a(14) =33a(15) =34a(16) =35a(17) =44a(18) =45a(19) =46a(20) =47a(21) =55a(22) =56a(23) =57a(24) =58a(25) =59a(26) =66a(27) =67a(28) =68a(29) =69