0,6

A number m is a child of n if the binary representation of n has a 1 in every position where the binary representation of m has a 1.

In other words, this tells us how closely (in Hamming weight) we can approximate n "from below" by a multiple of e.

Nadia Heninger and N. J. A. Sloane, Table of n, a(n) for n = 0..5000

N. J. A. Sloane, Fortran program for this and related sequences

If n = 14 = 1110_2, take k=2, ke = 6 = 110_2, which is Hamming distance 1 from n. This is the best we can do, so a(14) = 1.

(Fortran) See Sloane link.

For e=2 and 4 through 9 see A000035 and A140081 through A140086.

Cf. A140137, A140138, A140200-A140206.

Sequence in context: A025886 A117355 A086966 * A065359 A087372 A036431

Adjacent sequences: A140077 A140078 A140079 * A140081 A140082 A140083

nonn

Nadia Heninger and N. J. A. Sloane, Jun 03 2008

approved