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%I #17 Aug 30 2016 18:24:29
%S 14,41,1144,1414,1441,4114,4141,4411,111444,114144,114414,114441,
%T 141144,141414,141441,144114,144141,144411,411144,411414,411441,
%U 414114,414141,414411,441114,441141,441411,444111,11114444,11141444
%N List of words over {1,4} with equal numbers of 1's and 4's.
%C This is to 4 as A214488 is to 3, and as A214218 is to 2. The subsequence of primes (when interpreted as decimal integers) is A087512.
%t Sort[FromDigits/@Flatten[Table[Permutations[PadRight[{},2n,{1,4}]],{n,4}],1]] (* _Harvey P. Dale_, Aug 30 2016 *)
%Y Cf. A214218, A214488.
%K nonn,base
%O 1,1
%A _Jonathan Vos Post_, Jul 19 2012
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