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A099905
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a(n) = binomial(2n-1, n-1) mod n.
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8
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0, 1, 1, 3, 1, 0, 1, 3, 1, 8, 1, 2, 1, 10, 0, 3, 1, 12, 1, 10, 3, 14, 1, 6, 1, 16, 10, 0, 1, 2, 1, 3, 21, 20, 21, 26, 1, 22, 10, 10, 1, 0, 1, 24, 0, 26, 1, 30, 1, 28, 27, 48, 1, 30, 16, 44, 48, 32, 1, 48, 1, 34, 6, 35, 35, 0, 1, 18, 33, 20, 1, 18, 1, 40, 60, 16, 0, 72, 1, 10, 10, 44, 1, 56, 75
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OFFSET
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1,4
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COMMENTS
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For p prime, a(p)=1. For n in A058008, a(n)=0.
For n the square of a prime p>=3 or the cube of a prime p>=5, a(n)=1. - Franz Vrabec, Mar 26 2008
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LINKS
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EXAMPLE
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a(11) = 352716 mod 11 = 1.
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MAPLE
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MATHEMATICA
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Table[Mod[Binomial[2n-1, n-1], n], {n, 90}] (* Harvey P. Dale, Dec 12 2011 *)
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PROG
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(PARI) a(n) = lift(Mod(binomial(2*n-1, n-1), n)) \\ Felix Fröhlich, Oct 17 2015
(Magma) [Binomial(2*n-1, n-1) mod n : n in [1..100]]; // Wesley Ivan Hurt, Oct 17 2015
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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