Periodic points under the map A053392 that adds consecutive pairs of digits and concatenates them.

Terms

a(0) =0a(1) =991a(2) =992a(3) =993a(4) =994a(5) =995a(6) =996a(7) =997a(8) =998a(9) =999a(10) =1810a(11) =1811a(12) =1812a(13) =1813a(14) =1814a(15) =1815a(16) =1816a(17) =1817a(18) =1818a(19) =6664a(20) =6665a(21) =6666a(22) =6667a(23) =6668a(24) =6669a(25) =33331a(26) =33332a(27) =33333a(28) =33334a(29) =33335