A014417 Representation of n in base of Fibonacci numbers (the Zeckendorf representation of n). Also, binary words starting with 1 not containing 11, with the word 0 added.

0, 1, 10, 100, 101, 1000, 1001, 1010, 10000, 10001, 10010, 10100, 10101, 100000, 100001, 100010, 100100, 100101, 101000, 101001, 101010, 1000000, 1000001, 1000010, 1000100, 1000101, 1001000, 1001001, 1001010, 1010000, 1010001, 1010010, 1010100, 1010101

Offset: 0

Author

Olivier Gérard

Keywords

• nonn
• easy
• base
• nice

Comments

Old name was: Representation of n in base of Fibonacci numbers (the Zeckendorf representation of n). Also, binary vectors not containing 11.

For n > 0, write n = Sum_{i >= 2} eps(i) Fib_i where eps(i) = 0 or 1 and no 2 consecutive eps(i) can be 1 (see A035517); then a(n) is obtained by writing the eps(i) in reverse order.

"One of the most important properties of the Fibonacci numbers is the special way in which they can be used to represent integers. Let's write j >> k <==> j >= k+2. Then every positive integer has a unique representation of the form n = F_k1 + F_k2 + ... + F_kr, where k1 >> k2 >> ... >> kr >> 0. (This is 'Zeckendorf's theorem.') ... We can always find such a representation by using a "greedy" approach, choosing F_k1 to be the largest Fibonacci number =< n, then choosing F_k2 to be the largest that is =< n - F_k1 and so on. Fibonacci representation needs a few more bits because adjacent 1's are not permitted; but the two representations are analogous." [Concrete Math.]

Since the binary representation of n in base of Fibonacci numbers allows only the successive bit pairs 00, 01, 10 and leaves 11 unused, we can use a ternary representation using all trits 0, 1, 2 where 00 --> 0, 01 --> 1 and 10 --> 2 (e.g. binary 1001010 as ternary 1022). - Daniel Forgues, Nov 30 2009

The same sequence also arises when considering the NegaFibonacci representations of the integers, as follows. Take the NegaFibonacci representations of n = 0, 1, 2, ... (A215022) and of n = -1, -2, -3, ... (A215023), sort the union of these two lists into increasing binary order, and we get A014417. Likewise the corresponding list of decimal representations, A003714, is the union of A215024 and A215025 sorted into increasing order. - N. J. A. Sloane, Aug 10 2012

Also, numbers, written in binary, such that no adjacent bits are equal to 1: A one-dimensional analog of the matrices considered in A228277/A228285, A228390, A228476, A228506 etc. - M. F. Hasler, Apr 27 2014

The sequence of final bits, starting with a(1), is the complement of the Fibonacci word A005614. - N. J. A. Sloane, Oct 03 2018

This representation is named after the Belgian Army doctor and mathematician Edouard Zeckendorf (1901-1983). - Amiram Eldar, Jun 11 2021

Examples

			The Zeckendorf expansions of 1, 2, ... are 1 = 1 = Fib_2 -> 1, 2 = 2 = Fib_3 -> 10, 3 = Fib_4 -> 100, 4 = 3+1 = Fib_4 + Fib_2 -> 101, 5 = 5 = Fib_5 -> 1000, 6 = 1+5 = Fib_2 + Fib_5 -> 1001, etc.
		

References

• Ronald L. Graham, Donald E. Knuth and Oren Patashnik, Concrete Mathematics. Addison-Wesley, Reading, MA, 1990.
• Donald E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.3, p. 169.
• Edouard Zeckendorf, Représentation des nombres naturels par une somme des nombres de Fibonacci ou de nombres de Lucas, Bull. Soc. Roy. Sci. Liège 41, 179-182, 1972.

Links

• T. D. Noe and Harry J. Smith, Table of n, a(n) for n = 0..10000
• Paul Dalenberg and Tom Edgar, Consecutive factorial base Niven numbers, Fibonacci Quart., Vol. 56, No. 2 (2018), pp. 163-166.
• Eric Duchene, Aviezri S. Fraenkel, Vladimir Gurvich, Nhan Bao Ho, Clark Kimberling, and Urban Larsson, Wythoff Wisdom, 43 pages, no date, apparently unpublished. See Table 2.
• Eric Duchene, Aviezri S. Fraenkel, Vladimir Gurvich, Nhan Bao Ho, Clark Kimberling, and Urban Larsson, Wythoff Wisdom, unpublished, no date. [Cached copy, with permission]
• Donald E. Knuth, Fibonacci multiplication, Appl. Math. Lett., Vol. 1, No. 1 (1988), pp. 57-60.
• Julien Leroy, Michel Rigo and Manon Stipulanti, Counting the number of non-zero coefficients in rows of generalized Pascal triangles, Discrete Mathematics, Vol. 340, No. 5 (2017), pp. 862-881.
• Casey Mongoven, Zeckendorf Representations no. 17 (a musical composition with A014417).
• Wikipedia, Zeckendorf's theorem.

Crossrefs

Cf. A000045, A003794, A007895, A035517, A130234, A215022, A215023, A215024, A215025.

a(n) = A003714(n) converted to binary.

Cf. also A005614, A189920, A104324, A213911.

See A104326 for dual Zeckendorf representation of n.

Programs

Haskell

a014417 0 = 0
a014417 n = foldl (\v z -> v * 10 + z) 0 $ a189920_row n
-- Reinhard Zumkeller, Mar 10 2013

Maple

A014417 := proc(n)
    local nshi,Z,i ;
    if n <= 1 then
        return n;
    end if;
    nshi := n ;
    Z := [] ;
    for i from A130234(n) to 2 by -1 do
        if nshi >= A000045(i) and nshi > 0 then
            Z := [1,op(Z)] ;
            nshi := nshi-A000045(i) ;
        else
            Z := [0,op(Z)] ;
        end if;
    end do:
    add( op(i,Z)*10^(i-1),i=1..nops(Z)) ;
end proc: # R. J. Mathar, Jan 31 2015

Mathematica

fb[n_Integer] := Block[{k = Ceiling[Log[GoldenRatio, n * Sqrt[5]]], t = n, fr = {}}, While[k > 1, If[t >= Fibonacci[k], AppendTo[fr, 1]; t = t - Fibonacci[k], AppendTo[fr, 0]]; k-- ]; FromDigits[fr]]; Table[ fb[n], {n, 0, 30}] (* Robert G. Wilson v, May 15 2004 *)
r = Map[Fibonacci, Range[2, 12]]; Table[Total[FromDigits@ PadRight[{1}, Flatten@ #] &@ Reverse@ Position[r, #] & /@ Abs@ Differences@ NestWhileList[Function[k, k - SelectFirst[Reverse@ r, # < k &]], n + 1, # > 1 &]], {n, 0, 33}] (* Michael De Vlieger, Mar 27 2016, Version 10 *)
FromDigits/@Select[Tuples[{0,1},7],SequenceCount[#,{1,1}]==0&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 14 2019 *)

PARI

Zeckendorf(n)=my(k=0,v,m); while(fibonacci(k)<=n,k=k+1); m=k-1; v=vector(m-1); v[1]=1; n=n-fibonacci(k-1); while(n>0,k=0; while(fibonacci(k)<=n,k=k+1); v[m-k+2]=1; n=n-fibonacci(k-1)); v \\ Ralf Stephan

PARI

Zeckendorf(n)= { local(k); a=0; while(n>0, k=0; while(fibonacci(k)<=n, k=k+1); a=a+10^(k-3); n=n-fibonacci(k-1); ); a }
{ for (n=0, 10000, Zeckendorf(n); print(n," ",a); write("b014417.txt", n, " ", a) ) } \\ Harry J. Smith, Jan 17 2009

Python

from sympy import fibonacci
def a(n):
    k=0
    x=0
    while n>0:
        k=0
        while fibonacci(k)<=n: k+=1
        x+=10**(k - 3)
        n-=fibonacci(k - 1)
    return x
print([a(n) for n in range(101)]) # Indranil Ghosh, Jun 07 2017, after PARI code by Harry J. Smith

Extensions

Comment layout fixed by Daniel Forgues, Dec 07 2009

Typo corrected by Daniel Forgues, Mar 25 2010

Definition expanded and Duchene et al. reference added by N. J. A. Sloane, Aug 07 2018

Name corrected by Michel Dekking, Nov 30 2020