This site is supported by donations to The OEIS Foundation.

"Email this user" was broken Aug 14 to 9am Aug 16. If you sent someone a message in this period, please send it again.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A027615 Number of 1's when n is written in base -2. 0
 0, 1, 2, 3, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 2, 3, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 5, 6, 4, 5, 3, 4, 2, 3, 4, 5, 3, 4, 5, 6, 4, 5, 6, 7, 5, 6, 4, 5, 3, 4, 5, 6, 4, 5, 3, 4, 2, 3, 4, 5, 3, 4, 2, 3, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 5, 6, 4, 5, 3, 4, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Base -2 is also called "negabinary". REFERENCES J.-P. Allouche and J. Shallit, Automatic Sequences, Cambridge Univ. Press, 2003, p. 164. LINKS Eric Weisstein's World of Mathematics, Negabinary. FORMULA a(n) = 3 * A072894(n+1) - 2n - 3. Proof by Nikolaus Meyberg, following a conjecture by Ralf Stephan. - R. J. Mathar, Jan 11 2013 CROSSREFS Cf. A072894. Sequence in context: A281367 A007720 A129968 * A053737 A033924 A276328 Adjacent sequences:  A027612 A027613 A027614 * A027616 A027617 A027618 KEYWORD nonn AUTHOR Pontus von BrÃ¶mssen, Nov 14 1997 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.