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Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock summing to 2 3 4 5 or 6.
1

%I #10 Nov 29 2018 10:37:28

%S 571,12457,271393,5914339,128887759,2808783981,61210372853,

%T 1333925956743,29069557621363,633497816232785,13805489867099657,

%U 300855891824364491,6556396659359553239,142880157321162697173,3113713281361245496797

%N Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock summing to 2 3 4 5 or 6.

%H R. H. Hardin, <a href="/A251384/b251384.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 23*a(n-1) - 21*a(n-2) - 119*a(n-3) + 66*a(n-4) + 72*a(n-5) - 32*a(n-6).

%F Empirical g.f.: x*(571 - 676*x - 3127*x^2 + 1846*x^3 + 1912*x^4 - 864*x^5) / (1 - 23*x + 21*x^2 + 119*x^3 - 66*x^4 - 72*x^5 + 32*x^6). - _Colin Barker_, Nov 29 2018

%e Some solutions for n=2:

%e ..1..2..1....2..0..2....1..2..2....0..2..1....1..2..1....2..2..2....1..0..1

%e ..0..2..0....2..2..0....2..0..0....0..1..0....0..1..2....1..0..2....1..2..1

%e ..2..0..0....1..1..2....0..1..1....1..1..2....1..1..2....1..2..1....2..1..0

%Y Column 2 of A251390.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 01 2014