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A039724 Numbers in base -2. 15
0, 1, 110, 111, 100, 101, 11010, 11011, 11000, 11001, 11110, 11111, 11100, 11101, 10010, 10011, 10000, 10001, 10110, 10111, 10100, 10101, 1101010, 1101011, 1101000, 1101001, 1101110, 1101111, 1101100, 1101101, 1100010, 1100011, 1100000, 1100001, 1100110, 1100111, 1100100 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

REFERENCES

M. Gardner, Knotted Doughnuts and Other Mathematical Entertainments. Freeman, NY, 1986, p. 101.

D. E. Knuth, The Art of Computer Programming. Addison-Wesley, Reading, MA, 1969, Vol. 2, p. 189.

LINKS

William A. Tedeschi, Table of n, a(n) for n=0..10000

Joerg Arndt, Matters Computational (The Fxtbook), p. 58-59

Matthew Szudzik, A Mathematica programming contest

Eric Weisstein, Negabinary (MathWorld)

Wikipedia, Negative base

EXAMPLE

2 = 4+(-2)+0 = 110, 3 = 4+(-2)+1 = 111, ..., 6 = (16)+(-8)+0+(-2)+0 = 11010.

MATHEMATICA

ToNegaBases[ i_Integer, b_Integer ] := FromDigits[ Rest[ Reverse[ Mod[ NestWhileList[ (#1 - Mod[ #1, b ])/-b &, i, #1 != 0 & ], b ] ] ] ]; Table[ ToNegaBases[ n, 2 ], {n, 0, 31} ]

PROG

(Haskell)

a039724 0 = 0

a039724 n = a039724 n' * 10 + m where

   (n', m) = if r < 0 then (q + 1, r + 2) else (q, r)

             where (q, r) = quotRem n (negate 2)

-- Reinhard Zumkeller, Jul 07 2012

CROSSREFS

Cf. A007088, A005351, A039723, A073785, A007608, A073786, A073787, A073788, A073789, A073790, A039723.

Cf. A212529 (negative numbers in base -2).

Sequence in context: A045884 A110736 A084292 * A008944 A106004 A113556

Adjacent sequences:  A039721 A039722 A039723 * A039725 A039726 A039727

KEYWORD

base,nice,nonn,easy,changed

AUTHOR

Robert Lozyniak (11(AT)onna.com)

EXTENSIONS

More terms from Eric W. Weisstein.

STATUS

approved

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Last modified September 2 00:06 EDT 2014. Contains 246317 sequences.