A214532 List of words over {1,9} with equal numbers of 1's and 9's.
19, 91, 1199, 1919, 1991, 9119, 9191, 9911, 111999, 119199, 119919, 119991, 191199, 191919, 191991, 199119, 199191, 199911, 911199, 911919, 911991, 919119, 919191, 919911, 991119, 991191, 991911, 999111, 11119999, 11191999
Offset: 1
Programs
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Mathematica
FromDigits/@(Flatten[Permutations/@Table[Join[Table[1,{n}],Table[9,{n}]],{n,4}],1]) (* Harvey P. Dale, Aug 20 2014 *)
Comments