List of words over {1,9} with equal numbers of 1's and 9's.

Terms

a(0) =19a(1) =91a(2) =1199a(3) =1919a(4) =1991a(5) =9119a(6) =9191a(7) =9911a(8) =111999a(9) =119199a(10) =119919a(11) =119991a(12) =191199a(13) =191919a(14) =191991a(15) =199119a(16) =199191a(17) =199911a(18) =911199a(19) =911919a(20) =911991a(21) =919119a(22) =919191a(23) =919911a(24) =991119a(25) =991191a(26) =991911a(27) =999111a(28) =11119999a(29) =11191999