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A208704 Number of nX3 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.

%I A208704 #26 Apr 06 2016 12:51:09
%S A208704 4,28,196,1372,9604,67228,470596,3294172,23059204,161414428,
%T A208704 1129900996,7909306972,55365148804,387556041628,2712892291396,
%U A208704 18990246039772,132931722278404,930522055948828,6513654391641796,45595580741492572
%N A208704 Number of nX3 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.
%C A208704 Column 3 of A208709.
%H A208704 R. H. Hardin, <a href="/A208704/b208704.txt">Table of n, a(n) for n = 1..210</a>
%F A208704 Empirical: a(n) = 7*a(n-1).
%F A208704 Empirical: a(n) = (A198480(n)+1)*2 = (A024075(n)+1)*4. [_Martin Ettl_, Nov 09 2012; revised Nov 13 2012]
%e A208704 Some solutions for n=4
%e A208704 ..0..0..0....0..1..1....0..0..1....0..1..1....0..1..1....0..1..1....0..0..1
%e A208704 ..1..0..1....1..0..1....0..0..1....0..1..1....1..0..0....1..0..1....0..1..1
%e A208704 ..1..0..1....0..1..0....0..0..1....0..1..1....1..1..1....1..1..1....0..0..0
%e A208704 ..1..0..1....0..1..0....1..1..1....0..1..1....1..0..1....1..0..1....0..1..0
%Y A208704 Cf. A270471.
%K A208704 nonn
%O A208704 1,1
%A A208704 _R. H. Hardin_, Mar 01 2012