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A118822
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Numerators of the convergents of the 2-adic continued fraction of zero given by A118821.
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4
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2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1, -2, 1, 0, 1, 2, -1, 0, -1
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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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Period 8 sequence: [2,-1,0,-1,-2,1,0,1].
G.f.: -x*(x-1)*(x^2+x+2) / ( 1+x^4 ).
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EXAMPLE
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at k = 4*n-1: 0/(-1)^n.
Convergents begin:
2/1, -1/-1, 0/-1, -1/1, -2/1, 1/0, 0/1, 1/-4,
2/-7, -1/3, 0/-1, -1/5, -2/9, 1/-4, 0/1, 1/-12,
2/-23, -1/11, 0/-1, -1/13, -2/25, 1/-12, 0/1, 1/-16,
2/-31, -1/15, 0/-1, -1/17, -2/33, 1/-16, 0/1, 1/-32, ...
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MAPLE
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MATHEMATICA
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Table[Sqrt[Mod[(n+1)^2, 8](-1)^Floor[(n+2)/4], {n, 100}] (* Wesley Ivan Hurt, Jan 01 2014 *)
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PROG
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(PARI) {a(n)=local(p=+2, q=-1, v=vector(n, i, if(i%2==1, p, q*2^valuation(i/2, 2)))); contfracpnqn(v)[1, 1]}
for(n=0, 80, print1(a(n), ", "))
(PARI) {a(n) = [2, -1, 0, -1, -2, 1, 0, 1][(n-1)%8+1]; } \\ Joerg Arndt, Jan 02 2014
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CROSSREFS
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KEYWORD
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frac,sign
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AUTHOR
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STATUS
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approved
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