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a(n) = n!*(n+1)!*(n+2)!*(n+3)!*(n+4)! / ( 2!*3!*4!*5! ).
2

%I #27 Aug 14 2023 08:27:29

%S 1,720,1814400,12192768000,184354652160000,5574884681318400000,

%T 309071606732292096000000,29374165503837040803840000000,

%U 4536546120412592581745049600000000

%N a(n) = n!*(n+1)!*(n+2)!*(n+3)!*(n+4)! / ( 2!*3!*4!*5! ).

%H Vincenzo Librandi, <a href="/A010799/b010799.txt">Table of n, a(n) for n = 1..96</a>

%H <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>

%t With[{c=Times@@(Range[2,5]!),l=Times@@@Partition[Range[20]!,5,1]}, #/c&/@l] (* _Harvey P. Dale_, Nov 10 2011 *)

%Y Column 5 in triangle A009963.

%K nonn,easy

%O 1,2

%A _N. J. A. Sloane_

%E Offset changed to 1 by _Seiichi Manyama_, Aug 14 2023