2,3

Except for 2 & 3 which are missing, is every integer present just once?

Table of n, a(n) for n=2..73.

f[n_] := BitXor[n, Floor[Log[2, n] + 1]]; t = Array[f, 75, 2];

Sequence in context: A074921 A182209 A120634 * A104178 A092874 A198109

Adjacent sequences: A178750 A178751 A178752 * A178754 A178755 A178756

easy,nonn

Robert G. Wilson v, Jun 09 2010

approved