%I #8 Mar 13 2021 17:01:14
%S 1,3,48,1566,126120,18153720,4357332000,1619499374640,883124275824000,
%T 677267024315091840,706022078404964428800,972890835488032591468800,
%U 1731258722423272253052441600,3900512495412914495014418918400,10938873545450798558110852249497600
%N Number of Hamiltonian cycles in the 3 X n rook graph.
%H Andrew Howroyd, <a href="/A341498/b341498.txt">Table of n, a(n) for n = 1..30</a>
%Y Column 3 of A269562.
%K nonn
%O 1,2
%A _Andrew Howroyd_, Feb 21 2021