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%I #17 Jan 06 2024 23:56:29
%S 0,2,18,64,186,380,838,1504,2242,4082,6266,8320,13010,17866,20218,
%T 31808,41390,50100,66530,82560,93446,123642,149398,171920,212166,
%U 249810,283678,340704,394882,428892,521406,594560,659382,764866,863154,954192,1086490,1212506,1326654,1498720,1660278
%N Number of regions in the hyperoctahedral (or cocktail party) graph of order n.
%H Scott R. Shannon, <a href="/A368755/a368755.png">Image for n = 2</a>.
%H Scott R. Shannon, <a href="/A368755/a368755_1.png">Image for n = 3</a>.
%H Scott R. Shannon, <a href="/A368755/a368755_2.png">Image for n = 4</a>.
%H Scott R. Shannon, <a href="/A368755/a368755_3.png">Image for n = 5</a>.
%H Scott R. Shannon, <a href="/A368755/a368755_4.png">Image for n = 6</a>.
%H Scott R. Shannon, <a href="/A368755/a368755_5.png">Image for n = 9</a>.
%H Scott R. Shannon, <a href="/A368755/a368755_6.png">Image for n = 10</a>.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CocktailPartyGraph.html">Cocktail Party Graph</a>.
%F a(n) = A368757(n) - A368756(n) + 1 by Euler's formula.
%Y Cf. A368756 (vertices), A368757 (edges), A368758 (k-gons), A129348, A193130, A282010.
%K nonn
%O 1,2
%A _Scott R. Shannon_, Jan 04 2024