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A208878 Number of 7Xn 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.

%I A208878 #7 Jul 22 2025 21:33:31
%S A208878 715,5826959,40380275500,271499374919883,1820216057105650386,
%T A208878 12201956787655438957014,81798476241280856702695038,
%U A208878 548357000894509223687629476021,3676054154412185019451007694406065
%N A208878 Number of 7Xn 0..3 arrays with new values 0..3 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 A208878 Row 7 of A208872
%H A208878 R. H. Hardin, <a href="/A208878/b208878.txt">Table of n, a(n) for n = 1..18</a>
%e A208878 Some solutions for n=4
%e A208878 ..0..0..0..0....0..1..0..0....0..0..0..1....0..0..0..1....0..0..0..0
%e A208878 ..1..2..1..1....1..0..1..2....1..1..0..0....1..1..2..1....1..1..1..1
%e A208878 ..1..0..2..1....1..2..0..0....0..1..2..1....2..1..0..3....0..2..3..3
%e A208878 ..3..3..1..2....3..1..3..0....3..1..3..0....2..3..0..0....3..2..0..0
%e A208878 ..0..2..3..1....1..0..1..3....0..1..0..2....0..2..1..3....3..0..2..0
%e A208878 ..2..0..0..1....2..3..1..3....0..1..0..2....2..0..1..0....2..3..3..0
%e A208878 ..0..2..2..0....2..2..1..1....0..1..1..1....2..0..1..2....0..0..3..2
%K A208878 nonn
%O A208878 1,1
%A A208878 _R. H. Hardin_ Mar 02 2012