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A104324
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The Fibonacci word over the nonnegative integers; or, the number of runs of identical bits in the binary Zeckendorf representation of n.
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10
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0, 1, 2, 2, 3, 2, 3, 4, 2, 3, 4, 4, 5, 2, 3, 4, 4, 5, 4, 5, 6, 2, 3, 4, 4, 5, 4, 5, 6, 4, 5, 6, 6, 7, 2, 3, 4, 4, 5, 4, 5, 6, 4, 5, 6, 6, 7, 4, 5, 6, 6, 7, 6, 7, 8, 2, 3, 4, 4, 5, 4, 5, 6, 4, 5, 6, 6, 7, 4, 5, 6, 6, 7, 6, 7, 8, 4, 5, 6, 6, 7, 6, 7, 8, 6, 7, 8, 8, 9, 2, 3, 4, 4, 5, 4, 5, 6, 4, 5, 6, 6, 7, 4, 5, 6, 6
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history;
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OFFSET
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0,3
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COMMENTS
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Image of 0 under repeated application of the morphism phi = {2i -> 2i,2i+1; 2i+1 -> 2i+2: i = 0,1,2,3,...}. - N. J. A. Sloane, Jun 30 2017
This sequence has some interesting fractal properties (plot it!).
First occurrence of k=0,1,2,... is at 0,1,2,4,7,12,20,33,54, ..., A000071(k+1): Fibonacci numbers - 1. - Robert G. Wilson v, Apr 25 2006
Read mod 2 gives the Fibonacci word A003849. The differences, halved, give A213911.
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REFERENCES
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E. 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.
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LINKS
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FORMULA
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EXAMPLE
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14 = 13+1 as a sum of Fibonacci numbers = 100001(in Fibonacci base) using the least number of 1's (Zeckendorf Rep): it consists of 3 runs: one 1, four 0's, one 1, so a(14)=3.
This sequence may be broken up into blocks of lengths 1,1,2,3,5,8,... (the nonzero Fibonacci numbers). The first occurrence of a number indicates the start of a new block. The first few blocks are:
0,
1,
2,2,
3,2,3,
4,2,3,4,4,
5,2,3,4,4,5,4,5,
6,2,3,4,4,5,4,5,6,4,5,6,6,
7,2,3,4,4,5,4,5,6,4,5,6,6,7,4,5,6,6,7,6,7,
8,2,3,4,4,5,4,5,6,4,5,6,6,7,4,5,6,6,7,6,7,8,4,5,6,6,7,6,7,8,6,7,8,8,
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MAPLE
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with(combinat, fibonacci):fib:=fibonacci: zeckrep:=proc(N)local i, z, j, n; i:=2; z:=NULL; n:=N; while fib(i)<=n do i:=i+1 od; print(i=fib(i)); for j from i-1 by -1 to 2 do if n>=fib(j) then z:=z, 1; n:=n-fib(j) else z:=z, 0 fi od; [z] end proc: countruns:=proc(s)local i, c, elt; elt:=s[1]; c:=1; for i from 2 to nops(s) do if s[i]<>s[i-1] then c:=c+1 fi od; c end proc: seq(countruns(zeckrep(n)), n=1..100);
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MATHEMATICA
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f[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-- ]; While[ fr[[1]] == 0, fr = Rest@fr]; Length@ Split@ fr]; Array[f, 105] (* Robert G. Wilson v, Apr 25 2006 *)
Nest[ReplaceAll[#, {t_ /; EvenQ[t] :> Sequence[t, t+1], t_ /; OddQ[t] :> t+1}] &, {0}, 10] (* Paolo Xausa, Apr 05 2024 *)
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PROG
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(Haskell)
import Data.List (group)
a104324 = length . map length . group . a213676_row
(PARI) phi(n) = if (n%2, n+1, [n, n+1]);
vphi(v) = nv = []; for (k=1, #v, nv = concat(nv, phi(v[k])); ); nv;
lista(nn) = {v = [0]; for (i=1, nn, v = vphi(v); ); v; } \\ Michel Marcus, Oct 10 2017
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CROSSREFS
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See also the Fibonacci word A003849.
See A288576 for another view of the initial blocks.
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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