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A335265
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a(n) = Denominator(-4*n^2*Zeta(1 - n)^2*(1 - 2^n)) for n >= 1, a(0) = 1.
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3
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1, 1, 3, 1, 15, 1, 7, 1, 15, 1, 33, 1, 455, 1, 3, 1, 255, 1, 133, 1, 33, 1, 69, 1, 455, 1, 3, 1, 435, 1, 2387, 1, 255, 1, 3, 1, 319865, 1, 3, 1, 1353, 1, 43, 1, 345, 1, 141, 1, 7735
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) = denominator(Bernoulli(n)^2*(2^(n+2) - 4)).
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EXAMPLE
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Rational sequence starts: 0, 1, 1/3, 0, 1/15, 0, 1/7, 0, 17/15, 0, 775/33, 0, 477481/455, ...
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MAPLE
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a := s -> `if`(s = 0, 0, -4*s^2*Zeta(1 - s)^2*(1 - 2^s)):
seq(denom(a(s)), s = 0..24);
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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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