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A030301
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n-th run has length 2^(n-1).
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8
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0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = 0 iff n has an odd number of digits in binary, = 1 otherwise. - Henry Bottomley, Apr 06 2000
a(n) = (1/2)*{1-(-1)^floor(log(n)/log(2))}. - Benoit Cloitre, Nov 22 2001
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MATHEMATICA
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Table[{PadRight[{}, 2^(n-1), 0], PadRight[{}, 2^n, 1]}, {n, 1, 8, 2}]//Flatten (* Harvey P. Dale, Apr 12 2023 *)
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PROG
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(PARI) a(n)=if(n<1, 0, 1-length(binary(n))%2)
(PARI) a(n)=if(n<1, 0, if(n%2==0, -a(n/2)+1, -a((n-1)/2)+1-(((n-1)/2)==0))) /* Ralf Stephan */
(Magma) [Floor(Log(n)/Log(2)) mod 2: n in [1..100]]; // Vincenzo Librandi, Jun 23 2015
(Python)
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CROSSREFS
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Characteristic function of A053754 (after its initial 0).
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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