This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A139353 Let the binary expansion of n be n = Sum_{k} 2^{r_k}, let e(n) be the number of r_k's that are even, o(n) the number that are odd; sequence gives e(n)*o(n). 3

%I

%S 0,0,0,1,0,0,1,2,0,1,0,2,1,2,2,4,0,0,1,2,0,0,2,3,1,2,2,4,2,3,4,6,0,1,

%T 0,2,1,2,2,4,0,2,0,3,2,4,3,6,1,2,2,4,2,3,4,6,2,4,3,6,4,6,6,9,0,0,1,2,

%U 0,0,2,3,1,2,2,4,2,3,4,6,0,0,2,3,0,0,3,4,2,3,4,6,3,4,6,8,1,2,2

%N Let the binary expansion of n be n = Sum_{k} 2^{r_k}, let e(n) be the number of r_k's that are even, o(n) the number that are odd; sequence gives e(n)*o(n).

%C e(n)+o(n) = A000120(n), the binary weight of n.

%e If n = 43 = 2^0+2^2+2^3+2^5, e(43)=1, o(43)=3.

%o See link in A139351 for Fortran program.

%Y Cf. A000120, A139351-A139355, A039004, A139370-A139373.

%K nonn

%O 0,8

%A _Nadia Heninger_ and _N. J. A. Sloane_, Jun 07 2008

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 16 21:59 EST 2019. Contains 320200 sequences. (Running on oeis4.)