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%I #6 May 31 2019 20:32:09
%S 1,2,4,6,10,12,20,28,40,70,72,84,90,140,198,220,252,264,308,504,572,
%T 728,858,924,1092,1560,1716,1820,1848,2520,2860,3432,3960,4420,4760,
%U 5304,6120,6864,8976,9724,12870,12920,14586,15504,16796,21318,25740
%N Numbers of the form (2i)! (2j)! / i! j! (i + j)!.
%e 90 is in the sequence because for a&b = 3&5, 6! 10!/(3! 5! 8!) = 90.
%t Flatten[Table[((2i)!(2j)!)/(i! j! (i+j)!),{i,0,10},{j,0,10}]]//Union (* _Harvey P. Dale_, May 31 2019 *)
%K nonn
%O 1,2
%A _Robert G. Wilson v_, Mar 19 2002
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