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A123621
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Greatest k <= n/2 such that n divides binomial(n,k).
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1
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0, 1, 1, 1, 2, 1, 3, 3, 4, 4, 5, 6, 6, 5, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 15, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 28, 28, 28, 29, 29, 30, 29, 31, 31, 32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 37, 37
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OFFSET
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1,5
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LINKS
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FORMULA
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a(p) = floor(p/2) for primes p.
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MATHEMATICA
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gk[n_]:=Module[{k=Floor[n/2]}, While[!Divisible[Binomial[n, k], n], k--]; k]; Array[gk, 80] (* Harvey P. Dale, Nov 22 2013 *)
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PROG
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(PARI) a(n) = if (n>1, my(k=n\2); while (binomial(n, k) % n, k--); k, 0); \\ Michel Marcus, Nov 06 2022
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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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