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

Offset: 0

Author

Max Alekseyev, Oct 08 2023

Keywords

• nonn

Comments

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

Crossrefs

Cf. A003418, A139550, A366369.

Programs

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;

Formula

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

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