%I #9 Oct 26 2023 00:34:00

%S 1,1,2,4,12,48,192,960,5760,34560,241920,1935360,15482880,139345920,

%T 1393459200,13934592000,153280512000,1839366144000,22072393728000,

%U 286941118464000,4017175658496000,56240459218944000

%N Ratios of successive terms are 1,2,2,3,4,4,5,6,6,...

%H Harvey P. Dale, <a href="/A004527/b004527.txt">Table of n, a(n) for n = 0..480</a>

%t FoldList[Times,1,Flatten[Append[#,Last[#]]&/@Partition[Range[20],2]]] (* _Harvey P. Dale_, Oct 15 2011 *)

%K nonn

%O 0,3

%A _N. J. A. Sloane_