OFFSET
1,1
COMMENTS
n such that there are as many odd as even terms in the orbit f(n), f(f(n)), f(f(f(n))), ..., 1, where f(k) = Floor(k/2).
FORMULA
A037861(Floor(n/2)) = 0.
EXAMPLE
floor(18/2) = 9 = 1001 (base 2) has the same number of 1's as 0's. So 18 is a term of the sequence.
Also the orbit corresponding to 18 is 9, 4, 2, 1, which has an equal number (i.e. 2) of odd and even terms.
MATHEMATICA
Select[Range[500], DigitCount[Floor[#/2], 2, 1]==DigitCount[Floor[#/2], 2, 0]&] (* Harvey P. Dale, Jan 14 2014 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Joseph L. Pe, Jan 21 2002
EXTENSIONS
Extended and edited by John W. Layman, Jan 30 2002
New definition by Jonathan Sondow, Jun 10 2011
STATUS
approved