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A221668 Sum of neighbor maps: number of 3Xn binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their horizontal, diagonal and antidiagonal neighbors in a random 0..2 3Xn array.

%I A221668 #6 Jul 23 2025 02:06:29
%S A221668 8,48,512,3772,31744,262144,2097152,16728064,134140928,1073741824,
%T A221668 8587837440,68719476736,549755813888,4397939335680,35184372088832,
%U A221668 281474976710656,2251796592459776,18014398509481984,144115185909972992
%N A221668 Sum of neighbor maps: number of 3Xn binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their horizontal, diagonal and antidiagonal neighbors in a random 0..2 3Xn array.
%C A221668 Row 3 of A221666
%H A221668 R. H. Hardin, <a href="/A221668/b221668.txt">Table of n, a(n) for n = 1..210</a>
%e A221668 Some solutions for n=3
%e A221668 ..0..1..0....1..1..0....1..1..1....1..0..0....1..0..1....1..1..1....1..0..0
%e A221668 ..0..1..0....1..1..1....1..0..1....0..1..0....0..1..1....1..0..1....0..1..1
%e A221668 ..0..1..1....1..1..0....1..1..1....1..0..0....0..0..1....1..0..1....0..0..0
%K A221668 nonn
%O A221668 1,1
%A A221668 _R. H. Hardin_ Jan 21 2013