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%I #8 Oct 27 2018 06:21:17
%S 1,5,12,27,73,154,358,872,1871,4438,10338,22880,54100,123711,279854,
%T 655190,1491102,3413413,7919449,18045604,41514375,95741087,218782546,
%U 503899032,1158409848,2653808377,6109601340,14027233372,32187863462
%N Number of n X 2 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of elements above it or three plus the sum of the elements diagonally to its northwest, modulo 4.
%H R. H. Hardin, <a href="/A240187/b240187.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-2) + 10*a(n-3) - a(n-4) - 5*a(n-5) - 15*a(n-6) + a(n-7) + 4*a(n-8) + 2*a(n-9) + 10*a(n-10) + 5*a(n-11) - 6*a(n-13).
%F Empirical g.f.: x*(1 + 5*x + 10*x^2 + 7*x^3 - 10*x^5 - 6*x^6 - 5*x^7 - 6*x^8 + 4*x^9 + 4*x^10 + 6*x^11) / (1 - 2*x^2 - 10*x^3 + x^4 + 5*x^5 + 15*x^6 - x^7 - 4*x^8 - 2*x^9 - 10*x^10 - 5*x^11 + 6*x^13). - _Colin Barker_, Oct 27 2018
%e Some solutions for n=4:
%e ..2..0....2..0....2..0....2..0....2..0....2..0....2..0....2..0....2..0....2..0
%e ..1..0....1..0....1..3....2..0....2..0....1..3....1..3....2..0....2..3....1..3
%e ..2..3....2..3....1..2....2..0....2..3....2..1....2..3....2..0....2..3....2..3
%e ..1..2....1..3....2..3....1..0....2..3....1..2....1..0....2..0....1..0....1..2
%Y Column 2 of A240192.
%K nonn
%O 1,2
%A _R. H. Hardin_, Apr 02 2014
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