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Number of n X n binary arrays, symmetric under 90-degree rotation, with every 1 adjacent to at least one other 1 both bishopwise and rookwise but with no three 1s in a row bishopwise or rookwise.
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%I #5 Nov 25 2018 12:29:36

%S 1,2,1,3,2,10,36,77,170,1539,2778,26239,152082,1317122,7797811,

%T 129473317,857792500,17986500145,205469564882

%N Number of n X n binary arrays, symmetric under 90-degree rotation, with every 1 adjacent to at least one other 1 both bishopwise and rookwise but with no three 1s in a row bishopwise or rookwise.

%K nonn

%O 1,2

%A _R. H. Hardin_, Sep 15 2008