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

Author

Jonathan Vos Post, Jul 20 2012

Keywords

• nonn
• base
• easy

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.

Crossrefs

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

Programs

Mathematica

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