a(n+1) is the least integer > a(n) containing all digits of a(n); a(1)=2.

Terms

a(0) =2a(1) =12a(2) =21a(3) =102a(4) =120a(5) =201a(6) =210a(7) =1002a(8) =1020a(9) =1200a(10) =2001a(11) =2010a(12) =2100a(13) =10002a(14) =10020a(15) =10200a(16) =12000a(17) =20001a(18) =20010a(19) =20100a(20) =21000a(21) =100002a(22) =100020a(23) =100200a(24) =102000a(25) =120000a(26) =200001a(27) =200010a(28) =200100a(29) =201000