A366368 - OEIS

A366368

a(n) = LCM of pairwise products of distinct integers from {1,2,...,n}.

1, 1, 2, 6, 24, 120, 360, 2520, 10080, 30240, 151200, 1663200, 1663200, 21621600, 151351200, 151351200, 605404800, 10291881600, 30875644800, 586637251200, 586637251200, 586637251200, 6453009763200, 148419224553600, 148419224553600, 742096122768000, 9647249595984000, 28941748787952000

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OFFSET

0,3

COMMENTS

A003418(n) divides a(n), which in turn divides A003418(n)^2. Furthermore, A003418(n)^2 / a(n) = A366369(n) is squarefree.

LINKS

Table of n, a(n) for n=0..27.

FORMULA

a(n) = A003418(n)^2 / A366369(n).

a(n) = A003418(n) * A139550(n) = A003418(n) * A003418(floor(n/2)).

PROG

(PARI) a366368(n) = my(k, r); r=1; forprime(p=2, n, k=logint(n, p); r *= p^(2*k - (n<2*p^k)) ); r;