A056060 The powerfree part of the central binomial coefficients.

1, 2, 3, 6, 10, 5, 35, 70, 14, 7, 462, 231, 429, 429, 715, 1430, 24310, 12155, 92378, 46189, 88179, 88179, 1352078, 676039, 52003, 52003, 7429, 7429, 1077205, 1077205, 33393355, 66786710, 43214930, 21607465, 181502706, 90751353, 176726319, 176726319, 7658140490

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..3388

Formula

a(n) = A055231(A001405(n)).

Example

n=14, binomial(14,7) = 3432 = 8*3*11*13. The largest square divisor is 4, and the squarefree part is 858. So GCD(4,858) = 2 and a(14) = 858/2 = 429.

Mathematica

a[n_] := Denominator[(b = Binomial[n, Floor[n/2]])/(Times @@ First /@ FactorInteger[b])^2]; Array[a, 36] (* Amiram Eldar, Sep 05 2020 *)

Crossrefs

Cf. A001405, A000188, A008833, A007913, A055229, A055231, A046098, A034974, A056056, A056057, A056058, A056059, A056060, A056061.

Sequence in context: A276946 A191542 A191668 * A056058 A352722 A028255

Adjacent sequences: A056057 A056058 A056059 * A056061 A056062 A056063

Keyword

nonn

Author

Labos Elemer, Jul 26 2000

Extensions

New name and more terms from Amiram Eldar, Sep 05 2020

Status

approved