A144244 - OEIS

A144244

Number of n X n binary arrays, symmetric under 180 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.

%I #3 Mar 31 2012 12:35:07

%S 1,2,1,9,24,94,870,7731,58940,1518701,25116276,780979887,31966477480

%N Number of n X n binary arrays, symmetric under 180 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