Smallest number distinct from n, not occurring earlier and having in binary representation exactly as many ones as n.
2, 1, 5, 8, 3, 9, 11, 4, 6, 12, 7, 10, 14, 13, 23, 32, 18, 17, 21, 24, 19, 25, 15, 20, 22, 28
2 seqfan posts
Wed Apr 8 00:55:37 CEST 2009 [seqfan] Re: Symmetric Relations and Self-Inverse Permutations