A028692 23-factorial numbers.

1, 22, 11616, 141320256, 39547060439040, 254538406080331591680, 37680818974206486508802211840, 128296611269497862923425473853914480640, 10047034036599529256387830050150921763777884979200, 18096242094820543236399273859296273669601076798103392511590400

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..38

Index entries for sequences related to factorial numbers.

Formula

From Amiram Eldar, Jul 14 2025: (Start)

a(n) = Product_{k=1..n} (23^k-1).

a(n) ~ c * 23^(n*(n+1)/2), where c = Product_{k>=1} (1 - 1/23^k) = 0.954631535623... . (End)

Mathematica

FoldList[ #1 (23^#2-1)&, 1, Range[ 20 ] ]
a[n_] := Abs[QPochhammer[23, 23, n]]; Array[a, 10, 0] (* Amiram Eldar, Jul 14 2025 *)

Prog

(PARI) a(n) = prod(k = 1, n, 23^k - 1); \\ Amiram Eldar, Jul 14 2025

Crossrefs

Cf. A005329, A027871, A027637, A027872, A027873, A027875, A027876, A027877, A027878, A027879, A027880, A028693, A028694.

Sequence in context: A370314 A229346 A254654 * A127486 A232847 A191946

Adjacent sequences: A028689 A028690 A028691 * A028693 A028694 A028695

Keyword

nonn

Author

Olivier Gérard

Status

approved