A178754 a(n) = n XOR floor(Log_2(n)), where XOR is bitwise XOR.

1, 3, 2, 6, 7, 4, 5, 11, 10, 9, 8, 15, 14, 13, 12, 20, 21, 22, 23, 16, 17, 18, 19, 28, 29, 30, 31, 24, 25, 26, 27, 37, 36, 39, 38, 33, 32, 35, 34, 45, 44, 47, 46, 41, 40, 43, 42, 53, 52, 55, 54, 49, 48, 51, 50, 61, 60, 63, 62, 57, 56, 59, 58, 70, 71, 68, 69, 66, 67, 64, 65, 78

Offset

1,2

Comments

This sequence is not a permutation of the integers which is self-inverse. But is it a permutation?

Links

Table of n, a(n) for n=1..72.

Mathematica

f[n_] := BitXor[n, Floor[ Log[2, n]]]; Array[f, 75];

Crossrefs

Sequence in context: A125764 A023897 A267100 * A276446 A100527 A276445

Adjacent sequences: A178751 A178752 A178753 * A178755 A178756 A178757

Keyword

easy,nonn

Author

Robert G. Wilson v, Jun 09 2010

Status

approved