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Base -2 is also called "negabinary".
J.-P. Allouche and J. Shallit, Automatic Sequences, Cambridge Univ. Press, 2003, p. 164.
Table of n, a(n) for n=0..80.
Eric Weisstein's World of Mathematics, Negabinary.
a(n) = 3 * A072894(n+1) - 2n - 3. Proof by Nikolaus Meyberg, following a conjecture by Ralf Stephan. - R. J. Mathar, Jan 11 2013
Sequence in context: A104246 A007720 A129968 * A053737 A033924 A276328
Adjacent sequences: A027612 A027613 A027614 * A027616 A027617 A027618
Pontus von Brömssen, Nov 14 1997