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a(n) = (3n)!/(3!n!).
(Formerly M5320)
2

%I M5320 #25 Feb 02 2022 04:00:45

%S 1,60,10080,3326400,1816214400,1482030950400,1689515283456000,

%T 2564684200286208000,5001134190558105600000,

%U 12182762888199545241600000,36255902355281846639001600000,129433571408356192501235712000000,545950804200446419970212233216000000

%N a(n) = (3n)!/(3!n!).

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H T. D. Noe, <a href="/A001525/b001525.txt">Table of n, a(n) for n = 1..100</a>

%t Table[(3 n)!/(3! n!), {n, 20}] (* _Harvey P. Dale_, May 25 2011 *)

%Y Equals A064350/3!, row sums of A157704/3! and row sums of A157705/3!.

%K nonn

%O 1,2

%A _N. J. A. Sloane_

%E More terms from _Harvey P. Dale_, May 25 2011