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A240187 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. 1

%I

%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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Last modified October 26 00:52 EDT 2021. Contains 348256 sequences. (Running on oeis4.)