This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A063695 Remove even-positioned bits from the binary expansion of n. 4
 0, 0, 2, 2, 0, 0, 2, 2, 8, 8, 10, 10, 8, 8, 10, 10, 0, 0, 2, 2, 0, 0, 2, 2, 8, 8, 10, 10, 8, 8, 10, 10, 32, 32, 34, 34, 32, 32, 34, 34, 40, 40, 42, 42, 40, 40, 42, 42, 32, 32, 34, 34, 32, 32, 34, 34, 40, 40, 42, 42, 40, 40, 42, 42, 0, 0, 2, 2, 0, 0, 2, 2, 8, 8, 10, 10, 8, 8, 10, 10, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..10000 R. Stephan, Some divide-and-conquer sequences ... R. Stephan, Table of generating functions FORMULA a(n) = 2*(floor(n/2)-a(floor(n/2))). - Vladeta Jovovic, Feb 23 2003 G.f. 1/(1-x) * sum(k>=0, (-2)^k*2t^2/(1-t^2), t=x^2^k). Members of A004514 written twice. - Ralf Stephan, Oct 06 2003 a(n) = 4 * a(floor(n / 4)) + 2 * floor(n mod 4 / 2). - Reinhard Zumkeller, Sep 26 2015 EXAMPLE E.g. a(25) = 8 because 25 = 11001 in binary and when we AND this with 1010 we are left with 1000 = 8. MAPLE [seq(every_other_pos(j, 2, 1), j=0..120)]; Function every_other_pos given at A063694. PROG (Haskell) a063695 0 = 0 a063695 n = 4 * a063695 n' + 2 * div q 2             where (n', q) = divMod n 4 -- Reinhard Zumkeller, Sep 26 2015 CROSSREFS A001477[n] = A063694[n]+a[n] Sequence in context: A225869 A039972 A031124 * A081417 A133388 A282516 Adjacent sequences:  A063692 A063693 A063694 * A063696 A063697 A063698 KEYWORD nonn AUTHOR Antti Karttunen, Aug 03 2001 STATUS approved

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

Last modified October 23 19:34 EDT 2018. Contains 316530 sequences. (Running on oeis4.)