This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A015005 #32 Jul 06 2025 10:11:45
%S A015005 1,1,7,301,77959,121226245,1131162092095,63330372050122765,
%T A015005 21274128570193389587095,42878835824239014254983869205,
%U A015005 518543838148941095553869851505328175,37625235473766496167083515195884075739704925,16380389585902052954270520869620904155598347770499975
%N A015005 q-factorial numbers for q=6.
%H A015005 Vincenzo Librandi, <a href="/A015005/b015005.txt">Table of n, a(n) for n = 0..50</a>
%H A015005 <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>.
%F A015005 a(n) = Product_{k=1..n} (6^k-1)/(6-1).
%F A015005 a(0) = 1, a(n) = (6^n-1)*a(n-1)/5. - _Vincenzo Librandi_, Oct 25 2012
%F A015005 From _Amiram Eldar_, Jul 05 2025: (Start)
%F A015005 a(n) = Product_{k=1..n} A003464(k).
%F A015005 a(n) ~ c * 6^(n*(n+1)/2)/5^n, where c = A132034. (End)
%t A015005 RecurrenceTable[{a[1]==1, a[n]==((6^n - 1) * a[n-1])/5}, a, {n, 15}] (* _Vincenzo Librandi_, Oct 25 2012 *)
%t A015005 Table[QFactorial[n, 6], {n, 15}] (* _Bruno Berselli_, Aug 14 2013 *)
%o A015005 (Magma) [n le 1 select 1 else (6^n-1)*Self(n-1)/5: n in [1..15]]; // _Vincenzo Librandi_, Oct 25 2012
%Y A015005 Cf. A015001, A015002, A015004, A015006, A015007, A015008, A015009, A015011.
%Y A015005 Column q=6 of A069777.
%Y A015005 Cf. A003464, A132034.
%K A015005 nonn,easy
%O A015005 0,3
%A A015005 _Olivier Gérard_
%E A015005 a(0)=1 prepended by _Alois P. Heinz_, Sep 08 2021