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Number of perfect matchings in the 4 X n rook graph.
2

%I #8 Mar 14 2021 00:47:05

%S 1,3,16,132,2016,44928,1551744,68542848,4211122176,309852407808,

%T 29839376553984,3304540891072512,460231661327007744,

%U 71669823905083834368,13644939814369185890304,2845529932444144841981952,710399582113730769218174976,191237460565395319832268767232

%N Number of perfect matchings in the 4 X n rook graph.

%H Andrew Howroyd, <a href="/A341852/b341852.txt">Table of n, a(n) for n = 0..50</a>

%Y Row n=4 of A341850.

%K nonn

%O 0,2

%A _Andrew Howroyd_, Feb 21 2021