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Number of lower triangles of an n X n 0..4 array with each element differing from all of its horizontal and vertical neighbors by one
1

%I #6 Dec 18 2015 18:17:44

%S 5,14,66,458,4990,81014,2059822,78060014,4641074078,410310652370,

%T 57068977108754,11768868532345686,3829513291002131546,

%U 1842092248483706146126,1402261360946084657783246

%N Number of lower triangles of an n X n 0..4 array with each element differing from all of its horizontal and vertical neighbors by one

%C Column 4 of A194998

%H R. H. Hardin, <a href="/A194994/b194994.txt">Table of n, a(n) for n = 1..24</a>

%e Some solutions for 4X4

%e ..3........2........2........2........2........4........1........4

%e ..2.1......1.0......3.2......3.4......3.2......3.2......2.3......3.2

%e ..3.2.3....0.1.2....2.3.2....2.3.4....2.3.2....2.3.4....3.2.3....4.3.4

%e ..2.1.2.3..1.0.1.2..1.2.3.2..1.2.3.4..1.2.1.2..1.2.3.4..2.1.2.1..3.4.3.2

%K nonn

%O 1,1

%A _R. H. Hardin_ Sep 07 2011