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A123621 Greatest k <= n/2 such that n divides binomial(n,k). 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,5
LINKS
Eric Weisstein's World of Mathematics, Binomial Coefficient
FORMULA
A007318(n,a(n)) mod n = 0.
a(p) = floor(p/2) for primes p.
MATHEMATICA
gk[n_]:=Module[{k=Floor[n/2]}, While[!Divisible[Binomial[n, k], n], k--]; k]; Array[gk, 80] (* Harvey P. Dale, Nov 22 2013 *)
PROG
(PARI) a(n) = if (n>1, my(k=n\2); while (binomial(n, k) % n, k--); k, 0); \\ Michel Marcus, Nov 06 2022
CROSSREFS
Sequence in context: A097357 A342016 A360923 * A370592 A151662 A049786
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 03 2006
STATUS
approved

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)