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A046098
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Numbers n such that central binomial coefficient C(n, floor[n/2]) is squarefree.
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19
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1, 2, 3, 4, 5, 7, 8, 11, 17, 19, 23, 71
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OFFSET
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1,2
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COMMENTS
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No other n < 10^8. - T. D. Noe, Apr 06 2007
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LINKS
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Table of n, a(n) for n=1..12.
Eric Weisstein's World of Mathematics, Central Binomial Coefficient
Eric Weisstein's World of Mathematics, Squarefree
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MATHEMATICA
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Select[Range[100], SquareFreeQ[Binomial[#, Floor[#/2]]]&] (* From Harvey P. Dale, Mar 11 2011 *)
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PROG
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(PARI) is(n)=issquarefree(binomial(n, n\2)) \\ Charles R Greathouse IV, Jul 16, 2011
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CROSSREFS
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Cf. A001405.
Cf. A056651 (cubefree central binomial coefficients).
Sequence in context: A191168 A191166 A111795 * A057484 A091997 A124168
Adjacent sequences: A046095 A046096 A046097 * A046099 A046100 A046101
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KEYWORD
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nonn,hard,changed
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AUTHOR
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Eric W. Weisstein
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STATUS
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approved
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