

A046098


Numbers n such that central binomial coefficient C(n, floor[n/2]) is squarefree.


19



0, 1, 2, 3, 4, 5, 7, 8, 11, 17, 19, 23, 71
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OFFSET

1,3


COMMENTS

No other n < 10^8.  T. D. Noe, Apr 06 2007


LINKS

Table of n, a(n) for n=1..13.
Eric Weisstein's World of Mathematics, Central Binomial Coefficient
Eric Weisstein's World of Mathematics, Squarefree


MATHEMATICA

Select[Range[0, 100], SquareFreeQ[Binomial[#, Floor[#/2]]]&] (* Harvey P. Dale, Mar 11 2011 *)


PROG

(PARI) is(n)=issquarefree(binomial(n, n\2)) \\ Charles R Greathouse IV, Jul 16, 2011


CROSSREFS

Cf. A001405.
Cf. A056651 (cubefree central binomial coefficients).
Sequence in context: A238484 A241340 A111795 * A258085 A247350 A057484
Adjacent sequences: A046095 A046096 A046097 * A046099 A046100 A046101


KEYWORD

nonn,hard


AUTHOR

Eric W. Weisstein


EXTENSIONS

0 added by T. D. Noe, Mar 06 2014


STATUS

approved



