Smallest number not occurring earlier fitting the repeating pattern "99887766554433221100".

Terms

a(0) =9a(1) =98a(2) =8a(3) =7a(4) =76a(5) =6a(6) =5a(7) =54a(8) =4a(9) =3a(10) =32a(11) =2a(12) =1a(13) =100a(14) =99a(15) =88a(16) =77a(17) =66a(18) =55a(19) =44a(20) =33a(21) =22a(22) =1100a(23) =998a(24) =87a(25) =766a(26) =554a(27) =43a(28) =2100a(29) =9988