A214530 List of words over {1,7} with equal numbers of 1's and 7's.

17, 71, 1177, 1717, 1771, 7117, 7171, 7711, 111777, 117177, 117717, 117771, 171177, 171717, 171771, 177117, 177171, 177711, 711177, 711717, 711771, 717117, 717171, 717711, 771117, 771171, 771711, 777111

Offset

1,1

Comments

This is to 7 as A214524 is to 6, as A214522 is to 5, as A214521 is to 4, as A214488 is to 3, and as A214218 is to 2. The subsequence of primes (when interpreted as decimal integers) is A087514.

Links

Table of n, a(n) for n=1..28.

Mathematica

Sort[FromDigits/@Flatten[Table[Permutations[PadRight[{}, 2n, {1, 7}]], {n, 3}], 1]] (* Harvey P. Dale, Aug 30 2016 *)

Crossrefs

Cf. A214218, A214488, A214521, A214522, A214524.

Sequence in context: A069496 A047978 A050524 * A087514 A119625 A130748

Adjacent sequences: A214527 A214528 A214529 * A214531 A214532 A214533

Keyword

nonn,base,easy

Author

Jonathan Vos Post, Jul 20 2012

Status

approved