OFFSET
1,2
COMMENTS
The sequence is a quasi-inverse of A161560: For n >= 2, a(A161560(n+1)+1) = n or n-1. - Jaroslav Krizek, Jun 13 2009, corrected Jul 13 2012
Conjecture: Essentially partial sums of A036577 (true for at least 10000 terms). - Sean A. Irvine, Jul 17 2022
FORMULA
a(n) = A001969(n) - n + 1 for n >= 2. - Jaroslav Krizek, Jun 13 2009
EXAMPLE
a(5) = 5 because the fifth evil number = 9 and floor(9/2 + 1/2) = 5.
PROG
(PARI) a(n)=(2*n+hammingweight(n-1)%2-1)\2 \\ Charles R Greathouse IV, Mar 22 2013
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Michael Joseph Halm, May 13 2004
EXTENSIONS
Corrected and edited by Jaroslav Krizek, Jun 13 2009
STATUS
approved