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%I #7 Dec 31 2023 15:40:23
%S 15,2795,667478,163422914,40039156736,9810325806914,2403711876698218,
%T 588954110860577394,144304709913279198696,35357337571782719886214,
%U 8663205247528271356492160,2122646395773319892200238358
%N Number of 4 X n 0..3 arrays with new values 0..3 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 Row 4 of A208408.
%H R. H. Hardin, <a href="/A208411/b208411.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 226*a(n-1) +4747*a(n-2) -18294*a(n-3) -739509*a(n-4) -1661510*a(n-5) +17227605*a(n-6) +10151090*a(n-7) -98711047*a(n-8) -11588022*a(n-9) +195980121*a(n-10) -44074854*a(n-11) -121060656*a(n-12) +71173728*a(n-13) -10077696*a(n-14) for n>16.
%e Some solutions for n=4
%e ..0..0..0..1....0..1..0..0....0..1..1..1....0..0..0..0....0..0..0..1
%e ..1..2..1..1....2..0..3..0....0..0..0..1....0..1..1..2....0..1..1..0
%e ..0..2..0..3....2..0..3..1....0..1..0..0....1..0..1..3....0..1..1..0
%e ..0..0..2..1....1..2..0..2....0..1..1..1....1..3..3..1....0..0..0..1
%Y Cf. A208408.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 26 2012
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