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%I #14 Sep 08 2022 08:44:39
%S 1,-4,-84,8736,4551456,-11851991424,-154324780331904,
%T 10047160498728278016,3270561732706527788046336,
%U -5323179358400075453935368658944,-43320145405426340445710562789228109824,1762701221841919957075369153792221868461981696
%N q-factorial numbers for q=-5.
%H Vincenzo Librandi, <a href="/A015018/b015018.txt">Table of n, a(n) for n = 1..50</a>
%H <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>
%F Prod_{k=1}^{n} (q^k - 1) / (q - 1).
%F a(1) = 1, a(n) = ((-5)^n - 1)*a(n-1)/(-6). - _Vincenzo Librandi_, Oct 26 2012
%t RecurrenceTable[{a[1]==1, a[n]==(((-5)^n - 1) * a[n-1])/(-6)}, a, {n, 15}] (* _Vincenzo Librandi_, Oct 26 2012 *)
%o (Magma) [n le 1 select 1 else ((-5)^n - 1)*Self(n-1)/(-6): n in [1..18]]; // _Vincenzo Librandi_, Oct 26 2012
%K sign,easy
%O 1,2
%A _Olivier Gérard_
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