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A326579
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a(n) = n*denominator(n*Bernoulli(n-1)) for n >= 1 and a(0) = 0.
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4
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0, 1, 2, 6, 4, 30, 6, 42, 8, 90, 10, 66, 12, 2730, 14, 30, 16, 510, 18, 798, 20, 2310, 22, 138, 24, 13650, 26, 54, 28, 870, 30, 14322, 32, 5610, 34, 210, 36, 1919190, 38, 78, 40, 13530, 42, 1806, 44, 2070, 46, 282, 48, 324870, 50, 1122, 52, 1590, 54, 43890, 56
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OFFSET
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0,3
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COMMENTS
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Conjecture: For n>1: denominator(Bernoulli(n-1)) = n*denominator(n*Bernoulli(n-1)) <=> n is Korselt <=> n is prime or n is Carmichael.
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LINKS
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FORMULA
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a(2*n) = 2*n.
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MAPLE
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A326579 := n -> `if`(n = 0, 0, n*denom(n*bernoulli(n-1))): seq(A326579(n), n=0..56);
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PROG
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(PARI) a(n) = if (n, n*denominator(n*bernfrac(n-1)), 0); \\ Michel Marcus, Jul 19 2019
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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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