A354758 a(n) = Product_{k = ceiling(n/2)..n-1} A090252(k).

1, 1, 2, 6, 15, 60, 140, 1260, 2772, 36036, 153153, 1225224, 3325608, 76488984, 212469400, 4461857400, 11763078600, 364655436600, 1037865473400, 42552484409400, 107632754682600, 5058739470082200, 33514148989294575, 536226383828713200, 1665124033994425200

Offset

1,3

Comments

The prime divisors of a(n) are forbidden in A090252(n).

Links

Michael De Vlieger, Table of n, a(n) for n = 1..587

Rémy Sigrist, Representation of the prime divisors of a(n) (blue pixels) and A090252(n) (red pixels)

Rémy Sigrist, PARI program

Formula

gcd(a(n), A090252(n)) = 1.

Example

a(7) = A090252(4) * A090252(5) * A090252(6) = 5 * 4 * 7 = 140.

Mathematica

With[{s = Import["https://oeis.org/A090252/b090252.txt", "Data"][[1 ;; 25, -1]]}, Table[Product[s[[k]], {k, Ceiling[n/2], n - 1}], {n, Length[s]}]] (* Michael De Vlieger, Aug 28 2022 *)

Prog

(PARI) See Links section.

Crossrefs

A355057 is another version.

Cf. A090252, A354757.

Sequence in context: A027287 A192186 A243550 * A003268 A242792 A216811

Adjacent sequences: A354755 A354756 A354757 * A354759 A354760 A354761

Keyword

nonn

Author

Rémy Sigrist, Jun 06 2022

Status

approved