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A129722 Number of 0's in even position in all Fibonacci binary words of length n. A Fibonacci binary word is a binary word having no 00 subword. +0
3
0, 0, 1, 1, 5, 6, 19, 25, 65, 90, 210, 300, 654, 954, 1985, 2939, 5911, 8850, 17345, 26195, 50305, 76500, 144516, 221016, 411900, 632916, 1166209, 1799125, 3283145, 5082270, 9197455, 14279725, 25655489, 39935214, 71293590, 111228804 (list; graph; listen)
OFFSET

0,5

COMMENT

a(2n+1)=a(2n)+a(2n-1) (n>=1). a(2n+1)=A001871(n-1) (n>=1). a(2n)=A129720(2n)=A001870(n-1). a(n)=Sum(k*A129721(n,k), k=0..floor(n/2)).

FORMULA

G.f.=z^2/[(1+z-z^2)(1-z-z^2)^2].

EXAMPLE

a(4)=5 because in 1110', 1111, 1101, 10'10', 10'11, 0110', 0111, and 0101 one has altogether five 0's in even position (marked by ').

MAPLE

G:=z^2/(1-z-z^2)^2/(1+z-z^2): Gser:=series(G, z=0, 45): seq(coeff(Gser, z, n), n=0..42);

CROSSREFS

Cf. A001870, A001871, A129719, A129720, A129721.

Sequence in context: A063445 A031448 A056509 this_sequence A133608 A072577 A057520

Adjacent sequences: A129719 A129720 A129721 this_sequence A129723 A129724 A129725

KEYWORD

nonn

AUTHOR

Emeric Deutsch (deutsch(AT)duke.poly.edu), May 13 2007

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Last modified August 29 17:54 EDT 2008. Contains 143238 sequences.


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