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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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 19 16:08 EDT 2019. Contains 328223 sequences. (Running on oeis4.)