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A261505
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Numerator of Product_{k=1..n} (2k/(2k+1))^((-1)^A000120(k)).
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4
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3, 15, 45, 405, 2025, 6075, 91125, 1549125, 13942125, 23236875, 534448125, 64133775, 1731611925, 50216745825, 753251187375, 2259753562125, 7683162111225, 69148459001025, 207445377003075, 1037226885015375, 14866918685220375, 669011340834916875
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OFFSET
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1,1
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COMMENTS
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Empirically, the infinite product converges slowly to 1.62816 ± 10^(-5).
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LINKS
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MATHEMATICA
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Table[Numerator@ Product[(2 k/(2 k + 1))^((-1)^Plus @@ IntegerDigits[k, 2]), {k, 1, n}], {n, 22}] (* Michael De Vlieger, Aug 25 2015 *)
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PROG
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(PARI)
n = 22; R(k) = { if (hammingweight(k)%2, (2*k+1)/(2*k), (2*k)/(2*k+1)) };
p = vector(n); p[1] = R(1); for(i = 2, #p, p[i] = p[i-1] * R(i));
apply(numerator, p)
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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