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A073354 Binomial coefficient ( n, squarefree kernel(n) ). 2
1, 1, 1, 6, 1, 1, 1, 28, 84, 1, 1, 924, 1, 1, 1, 120, 1, 18564, 1, 184756, 1, 1, 1, 134596, 53130, 1, 2925, 40116600, 1, 1, 1, 496, 1, 1, 1, 1947792, 1, 1, 1, 847660528, 1, 1, 1, 2104098963720, 344867425584, 1, 1, 12271512, 85900584, 10272278170, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

a(n)=1 iff n is squarefree.

LINKS

Robert Israel, Table of n, a(n) for n = 1..3315

FORMULA

a(n) = binomial(n, A007947(n)).

MAPLE

f:= proc(n) local k;

  k:= convert(numtheory:-factorset(n), `*`);

  binomial(n, k)

end proc:

map(f, [$1..60]); # Robert Israel, May 07 2021

CROSSREFS

Cf. A007947, A005117, A073353, A066503, A064549, A003557.

Sequence in context: A050449 A316623 A108131 * A197420 A128423 A345628

Adjacent sequences:  A073351 A073352 A073353 * A073355 A073356 A073357

KEYWORD

nonn,look

AUTHOR

Reinhard Zumkeller, Jul 29 2002

STATUS

approved

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Last modified October 23 00:39 EDT 2021. Contains 348211 sequences. (Running on oeis4.)