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A281648
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(Numerator of Bernoulli(2*n)) read mod n.
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2
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0, 1, 1, 3, 0, 5, 0, 7, 1, 9, 0, 5, 0, 7, 5, 15, 0, 11, 0, 9, 1, 11, 0, 13, 0, 13, 19, 7, 0, 19, 0, 31, 11, 17, 0, 11, 0, 19, 13, 13, 0, 37, 0, 33, 35, 23, 0, 37, 0, 39, 34, 39, 0, 11, 5, 35, 19, 29, 0, 29, 0, 31, 61, 63, 0, 55, 0, 51, 23, 21, 0, 43, 0, 37, 50, 19
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OFFSET
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1,4
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COMMENTS
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Conjecture: a(n) == n-1 (mod n) if only if n = 6, 10 or n = 2^k for k >= 0. This is true for n <= 1024. - Seiichi Manyama, Jan 27 2017
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LINKS
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Seiichi Manyama, Table of n, a(n) for n = 1..1000
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FORMULA
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a(n) = A000367(n) mod n.
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MATHEMATICA
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f[n_] := Mod[Numerator[BernoulliB[2 n]], n]; Array[f, 77] (* Robert G. Wilson v, Jan 26 2017 *)
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PROG
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(Ruby)
def bernoulli(n)
ary = []
a = []
(0..n).each{|i|
a << 1r / (i + 1)
i.downto(1){|j| a[j - 1] = j * (a[j - 1] - a[j])}
ary << a[0]
}
ary
end
def A281648(n)
a = bernoulli(2 * n)
(1..n).map{|i| a[2 * i].numerator % i}
end
(PARI) a(n)=numerator(bernfrac(2*n))%n \\ Charles R Greathouse IV, Jan 27 2017
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CROSSREFS
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Cf. A000367, A060976, A069040, A070192, A070193, A281662.
Sequence in context: A049283 A141162 A160035 * A353154 A325962 A210451
Adjacent sequences: A281645 A281646 A281647 * A281649 A281650 A281651
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KEYWORD
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nonn
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AUTHOR
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Seiichi Manyama, Jan 26 2017
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STATUS
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approved
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