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A213369
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The twisted Stern sequence: a(0) = 0, a(1) = 1 and a(2n) = -a(n), a(2n + 1) = -a(n)-a(n + 1) for n>=1.
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6
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0, 1, -1, 0, 1, 1, 0, -1, -1, -2, -1, -1, 0, 1, 1, 2, 1, 3, 2, 3, 1, 2, 1, 1, 0, -1, -1, -2, -1, -3, -2, -3, -1, -4, -3, -5, -2, -5, -3, -4, -1, -3, -2, -3, -1, -2, -1, -1, 0, 1, 1, 2, 1, 3, 2, 3, 1, 4, 3, 5, 2, 5, 3, 4, 1, 5, 4, 7, 3, 8, 5, 7, 2, 7, 5, 8, 3, 7
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OFFSET
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0,10
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LINKS
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FORMULA
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MATHEMATICA
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a[0]=0; a[1]=1; a[n_] := a[n] = If[EvenQ[n], -a[n/2], -a[(n-1)/2]-a[(n+1)/2 ]]; Table[a[n], {n, 0, 77}] (* Jean-François Alcover, Oct 02 2018 *)
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PROG
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(Maxima) a[0]:0$ a[1]:1$ a[n]:=-a[floor(n/2)]-(1-(-1)^n)*a[floor((n-1)/2)+1]/2$ makelist(a[n], n, 0, 77); /* Bruno Berselli, Jun 15 2012 */
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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