For m=2,3,..., write m in bases m,m-1,...,3,2.

Terms

a(0) =10a(1) =10a(2) =11a(3) =10a(4) =11a(5) =100a(6) =10a(7) =11a(8) =12a(9) =101a(10) =10a(11) =11a(12) =12a(13) =20a(14) =110a(15) =10a(16) =11a(17) =12a(18) =13a(19) =21a(20) =111a(21) =10a(22) =11a(23) =12a(24) =13a(25) =20a(26) =22a(27) =1000a(28) =10a(29) =11