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A019300
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First n elements of Thue-Morse sequence A010060 read as a binary number.
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8
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0, 1, 3, 6, 13, 26, 52, 105, 211, 422, 844, 1689, 3378, 6757, 13515, 27030, 54061, 108122, 216244, 432489, 864978, 1729957, 3459915, 6919830, 13839660, 27679321, 55358643, 110717286, 221434573, 442869146, 885738292, 1771476585, 3542953171
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OFFSET
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0,3
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LINKS
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FORMULA
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MATHEMATICA
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With[{tm=Nest[Flatten[#/.{0->{0, 1}, 1->{1, 0}}]&, {0}, 7]}, Table[ FromDigits[ Take[tm, n], 2], {n, 40}]] (* Harvey P. Dale, Mar 25 2015 *)
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PROG
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(Scheme)
(define rdc(lambda(x)(if(null? (cdr x))'()(cons (car x) (rdc (cdr x))))))
; if a bit is 1, get 2^i, where i is the index of that bit from right-left
(define F (lambda (c i)(if (eq? c #\1) (expt 2 i) 0)))
; gathers the sum of 2^index for all indices corresponding to a 1
(define fn (lambda (x sum i stop)(if (eq? i stop) sum (fn (list->string (rdc (string->list x))) (+ sum (F (string-ref x (-(string-length x) 1)) i)) (+ i 1)stop))))
(define f (lambda (x)(fn (substring thue 0 (+ x 1)) 0 0 (string-length (substring thue 0 (+ x 1))) )))
(define thue "0110100110010110") ; Feel free to add Thue-Morse sequence of whatever length here
(PARI) first(n)=my(v=vector(n)); v[1]=1; for(k=2, n, v[k]=2*v[k-1]+hammingweight(k)%2); concat(0, v) \\ Charles R Greathouse IV, May 08 2016
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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