A015007 q-factorial numbers for q=8.

1, 1, 9, 657, 384345, 1799118945, 67375205371305, 20185139902805378865, 48378633136349277767794425, 927610024989668734297857360967425, 142287668466497494704440569679875994730825, 174605966461872393482359052970987514818406771638225

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..40

Index entries for sequences related to factorial numbers

Formula

a(n) = Product_{k=1..n} ((q^k - 1) / (q - 1)), with q=8.

a(0) = 1, a(n) = (8^n-1)*a(n-1)/7. - Vincenzo Librandi, Oct 26 2012

Mathematica

RecurrenceTable[{a[1]==1, a[n]==((8^n - 1) * a[n-1])/7}, a, {n, 15}] (* Vincenzo Librandi, Oct 26 2012 *)
Table[QFactorial[n, 8], {n, 15}] (* Bruno Berselli, Aug 14 2013 *)

Prog

(Magma) [n le 1 select 1 else (8^n-1)*Self(n-1)/7: n in [1..15]]; // Vincenzo Librandi, Oct 26 2012

Crossrefs

Cf. A015001, A015002, A015004, A015005, A015006, A015008, A015009, A015011.

Column q=8 of A069777.

Sequence in context: A020548 A091062 A221133 * A054327 A209964 A287937

Adjacent sequences: A015004 A015005 A015006 * A015008 A015009 A015010

Keyword

nonn,easy

Author

Olivier Gérard

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 08 2021

Status

approved