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%I #51 Jun 19 2022 11:29:45
%S 0,0,1,6,156,4800,208440,11939760,874681920,79795860480,8873760470400,
%T 1181869427692800,185755937440550400,34022680848982425600,
%U 7183771725162237004800,1732270657442505852672000,473131604733608510097408000,145308345869661566419795968000
%N Number of (undirected) Hamiltonian cycles in the n-crown graph.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CrownGraph.html">Crown Graph</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HamiltonianCycle.html">Hamiltonian Cycle</a>
%F a(n) = A094047(n)/2.
%Y Cf. A094047.
%K nonn
%O 1,4
%A _Eric W. Weisstein_, May 06 2019