

A214521


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


5



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
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OFFSET

1,1


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.


LINKS

Table of n, a(n) for n=1..30.


MATHEMATICA

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


CROSSREFS

Cf. A214218, A214488.
Sequence in context: A043227 A044007 A199710 * A064512 A118237 A326624
Adjacent sequences: A214518 A214519 A214520 * A214522 A214523 A214524


KEYWORD

nonn,base


AUTHOR

Jonathan Vos Post, Jul 19 2012


STATUS

approved



