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 A196431 Number of n X 3 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,1,0,3,4 for x=0,1,2,3,4. 2

%I #9 Mar 01 2018 05:47:20

%S 3,9,25,75,213,621,1801,5219,15133,43867,127195,368759,1069105,

%T 3099583,8986391,26053581,75535111,218993223,634910491,1840747761,

%U 5336740123,15472405305,44857970049,130053306249,377053674603,1093163086545

%N Number of n X 3 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,1,0,3,4 for x=0,1,2,3,4.

%C Every 0 is next to 0 2's, every 1 is next to 1 1's, every 2 is next to 2 0's, every 3 is next to 3 3's, every 4 is next to 4 4's.

%C Column 3 of A196436.

%H R. H. Hardin, <a href="/A196431/b196431.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = a(n-1) + 3*a(n-2) + 5*a(n-3) + 6*a(n-4) + 4*a(n-5) - 5*a(n-6) - 5*a(n-7) - a(n-8) + a(n-9).

%F Empirical g.f.: x*(1 + x)*(3 + 3*x + 4*x^2 + 4*x^3 - 4*x^4 - 4*x^5 - x^6 + x^7) / (1 - x - 3*x^2 - 5*x^3 - 6*x^4 - 4*x^5 + 5*x^6 + 5*x^7 + x^8 - x^9). - _Colin Barker_, Mar 01 2018

%e Some solutions for n=4:

%e ..0..0..0....1..1..0....1..1..0....0..1..1....0..1..0....1..1..0....0..0..0

%e ..0..0..0....0..0..1....0..0..0....1..0..0....0..1..0....0..0..0....0..1..1

%e ..1..0..0....0..0..1....0..0..1....1..0..1....1..0..1....1..0..1....0..0..0

%e ..1..0..0....0..0..0....0..0..1....0..0..1....1..0..1....1..0..1....0..0..0

%Y Cf. A196436.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 02 2011

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Last modified May 26 10:52 EDT 2024. Contains 372824 sequences. (Running on oeis4.)