A214521 List of words over {1,4} with equal numbers of 1's and 4's.

14, 41, 1144, 1414, 1441, 4114, 4141, 4411, 111444, 114144, 114414, 114441, 141144, 141414, 141441, 144114, 144141, 144411, 411144, 411414, 411441, 414114, 414141, 414411, 441114, 441141, 441411, 444111, 11114444, 11141444

Offset: 1

Author

Jonathan Vos Post, Jul 19 2012

Keywords

• nonn
• base

Comments

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.

Crossrefs

Cf. A214218, A214488.

Programs

Mathematica

Sort[FromDigits/@Flatten[Table[Permutations[PadRight[{},2n,{1,4}]],{n,4}],1]] (* Harvey P. Dale, Aug 30 2016 *)