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A252222 Number of (n+2) X (2+2) 0..2 arrays with every 3 X 3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4. 1

%I

%S 368,1028,3066,7724,22256,70284,219824,675264,2072804,6383492,

%T 19670396,60581792,186548780,574478144,1769185920,5448417444,

%U 16778894996,51672129164,159129275664,490053971084,1509168106704,4647627251072

%N Number of (n+2) X (2+2) 0..2 arrays with every 3 X 3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4.

%H R. H. Hardin, <a href="/A252222/b252222.txt">Table of n, a(n) for n = 1..210</a>

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

%F Empirical g.f.: 2*x*(184 - 38*x + 175*x^2 - 775*x^3 - 1019*x^4 - 337*x^5 + 127*x^6 + 115*x^7 + 3*x^8) / ((1 - x + 2*x^2 - x^3)*(1 - 2*x - 3*x^2 - x^3)). - _Colin Barker_, Dec 02 2018

%e Some solutions for n=4:

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

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

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

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

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

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

%Y Column 2 of A252228.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 15 2014

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Last modified October 24 20:35 EDT 2021. Contains 348233 sequences. (Running on oeis4.)