A139012 - OEIS

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A139012

Number of n X n symmetric binary matrices containing no more than three 1s in any 3 X 3 sub-block.

%I #4 Mar 31 2012 12:35:07

%S 1,2,7,20,146,1660,24266,619885,24951532,1491389352,141842503743,

%T 21156539568960,4861988525864115,1744688422871068399,

%U 977626718408600885914,851525107752786868842753

%N Number of n X n symmetric binary matrices containing no more than three 1s in any 3 X 3 sub-block.

%K nonn

%O 0,2

%A _R. H. Hardin_, May 31 2008