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1, 9, 33, 41, 129, 137, 161, 169, 513, 521, 545, 553, 641, 649, 673, 681, 2049, 2057, 2081, 2089, 2177, 2185, 2209, 2217, 2561, 2569, 2593, 2601, 2689, 2697, 2721, 2729, 8193, 8201, 8225, 8233, 8321, 8329, 8353, 8361, 8705, 8713, 8737, 8745, 8833, 8841, 8865, 8873, 10241
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OFFSET
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1,2
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COMMENTS
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Every positive odd integer m==3 (mod 8) is a unique sum of the form a(s)+2a(t), while other odd integers are not expressible in this form.
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LINKS
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FORMULA
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If f(x) = Sum_{n>=1}x^a(n), abs(x) < 1, then f(x)*f(x^2) = x^3/(1 - x^8).
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MATHEMATICA
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a[n_] := 2 * FromDigits[IntegerDigits[2*n-2, 2], 4] + 1; Array[a, 50] (* Amiram Eldar, Dec 16 2018 *)
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PROG
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(PARI) a145812(n) = 2*fromdigits(binary(n-1), 4) + 1;
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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