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A015002 q-factorial numbers for q=4. 2
1, 5, 105, 8925, 3043425, 4154275125, 22686496457625, 495586515116818125, 43304845277422684580625, 15136126045591163828042953125, 21161832960467051739150680807015625 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..50

Index entries for sequences related to factorial numbers

FORMULA

Prod_{k=1}^{n} (q^k - 1) / (q - 1).

a(1) = 1, a(n) = (4^n-1)*a(n-1)/3. - Vincenzo Librandi, Oct 27 2012

MATHEMATICA

RecurrenceTable[{a[1]==1, a[n]==((4^n - 1) * a[n-1])/3}, a, {n, 15}] (* Vincenzo Librandi, Oct 27 2012 *)

Table[QFactorial[n, 4], {n, 15}] (* Bruno Berselli, Aug 14 2013 *)

PROG

(MAGMA) [n le 1 select 1 else (4^n-1)*Self(n-1)/3: n in [1..15]]; // Vincenzo Librandi, Oct 22 2012

CROSSREFS

Sequence in context: A223043 A200851 A203471 * A059490 A204109 A093979

Adjacent sequences:  A014999 A015000 A015001 * A015003 A015004 A015005

KEYWORD

nonn,easy

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified June 21 21:27 EDT 2018. Contains 305644 sequences. (Running on oeis4.)