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Number of n X 1 0..4 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of elements above it, modulo 5.
1

%I #9 Oct 25 2018 12:24:42

%S 4,13,41,131,419,1339,4279,13675,43703,139667,446351,1426459,4558711,

%T 14568835,46559423,148795691,475524743,1519693075,4856670607,

%U 15521061307,49602570071,158521051427,506605276895,1619020970827,5174105015335

%N Number of n X 1 0..4 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of elements above it, modulo 5.

%H R. H. Hardin, <a href="/A239249/b239249.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) + 2*a(n-3).

%F Empirical g.f.: x*(4 + x + 2*x^2) / (1 - 3*x - 2*x^3). - _Colin Barker_, Oct 25 2018

%e Some solutions for n=5:

%e ..4....3....2....3....2....0....4....2....0....3....3....0....3....0....4....4

%e ..2....2....2....2....2....2....3....4....3....0....2....0....2....4....4....3

%e ..4....4....2....0....3....4....0....4....0....2....4....2....0....2....2....4

%e ..0....2....3....4....2....3....2....0....2....0....3....0....0....3....0....0

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

%Y Column 1 of A239256.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 13 2014