Ternary numbers consisting of a run of 2's, then a run of 0's, then a run of 1's.

Terms

a(0) =201a(1) =2001a(2) =2011a(3) =2201a(4) =20001a(5) =20011a(6) =20111a(7) =22001a(8) =22011a(9) =22201a(10) =200001a(11) =200011a(12) =200111a(13) =201111a(14) =220001a(15) =220011a(16) =220111a(17) =222001a(18) =222011a(19) =222201a(20) =2000001a(21) =2000011a(22) =2000111a(23) =2001111a(24) =2011111a(25) =2200001a(26) =2200011a(27) =2200111a(28) =2201111a(29) =2220001