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A222511 Number of 3Xn 0..1 arrays with exactly floor(3Xn/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

%I A222511 #6 Jul 23 2025 02:41:56
%S A222511 0,4,4,15,35,170,441,2192,5416,26660,66209,328121,816736,4074688,
%T A222511 10172187,51053330,127212627,643151980,1598614930,8135779154,
%U A222511 20183768037,103256080822,255983883834,1314494576457,3259213240495,16780895442470
%N A222511 Number of 3Xn 0..1 arrays with exactly floor(3Xn/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..1 order.
%C A222511 Row 3 of A222509
%H A222511 R. H. Hardin, <a href="/A222511/b222511.txt">Table of n, a(n) for n = 1..77</a>
%e A222511 All solutions for n=3
%e A222511 ..0..0..0....0..0..0....0..1..0....0..0..0
%e A222511 ..1..0..0....0..0..1....1..1..1....0..0..0
%e A222511 ..0..0..0....0..0..0....1..1..1....1..0..1
%K A222511 nonn
%O A222511 1,2
%A A222511 _R. H. Hardin_ Feb 23 2013