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A366794
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Binary encoding of the twos (-1's) in the balanced ternary representation of Per Nørgård's "infinity sequence".
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2
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0, 0, 1, 1, 0, 0, 2, 0, 1, 1, 0, 0, 1, 1, 2, 0, 0, 0, 2, 0, 0, 0, 1, 1, 2, 0, 0, 0, 0, 2, 3, 3, 1, 1, 0, 0, 1, 1, 2, 0, 0, 0, 1, 1, 0, 0, 2, 0, 1, 1, 2, 0, 1, 1, 0, 0, 2, 0, 1, 1, 0, 2, 4, 2, 0, 0, 2, 0, 0, 0, 1, 1, 2, 0, 0, 0, 0, 2, 3, 3, 0, 0, 1, 1, 0, 0, 2, 0, 1, 1, 0, 0, 1, 1, 2, 0, 2, 0, 0, 0, 0, 2, 3, 3, 0, 0
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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0,7
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COMMENTS
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The composer Per Nørgård's name is also written in the OEIS as Per Noergaard.
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LINKS
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FORMULA
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EXAMPLE
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A004718(254) = -7. In balanced ternary representation (see A117966) this is represented as -1*9 + 1*3 + -1*1. Taking the negative coefficients, and converting them to a binary string gives "101", which in base-2 (A007088) is equal to 5, therefore a(254) = 5.
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PROG
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(PARI)
up_to = 65536;
A004718list(up_to) = { my(v=vector(up_to)); v[1]=1; v[2]=-1; for(n=3, up_to, v[n] = if(n%2, 1+v[n>>1], -v[n/2])); (v); }; \\ From the code in A004718.
v004718 = A004718list(up_to);
A004718(n) = if(!n, n, v004718[n]);
A289814(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==2, 1, 0)), 2); };
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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