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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 (list; graph; refs; listen; history; text; internal format)
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: A293441 A306203 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

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Last modified December 15 20:00 EST 2019. Contains 330000 sequences. (Running on oeis4.)