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%I #8 Jul 05 2018 08:22:51
%S 8,23,71,225,722,2331,7548,24476,79423,257807,836973,2717446,8823199,
%T 28648292,93019712,302032007,980690055,3184277945,10339281402,
%U 33571429395,109005736508,353939387572,1149233948207,3731539152111
%N Number of n X 4 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.
%C Column 4 of A208637.
%H R. H. Hardin, <a href="/A208633/b208633.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 5*a(n-1) - 6*a(n-2) + a(n-3).
%F Empirical g.f.: x*(8 - 17*x + 4*x^2) / (1 - 5*x + 6*x^2 - x^3). - _Colin Barker_, Jul 05 2018
%e Some solutions for n=4:
%e ..0..0..1..0....0..0..0..0....0..0..1..0....0..0..1..0....0..1..0..1
%e ..1..0..1..0....1..1..1..0....1..0..1..1....1..0..1..0....1..0..1..0
%e ..0..1..0..1....0..0..1..1....0..1..0..1....1..0..1..0....0..1..0..1
%e ..1..0..1..0....1..0..0..1....0..1..0..0....1..0..1..1....0..1..0..1
%Y Cf. A208637.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 29 2012
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