%I #4 Dec 06 2014 18:09:27
%S 489,865,2089,5065,13031,36075,100307,282489,805963,2300981,6582921,
%T 18872307,54105547,155166259,445147549,1277038995,3663729245,
%U 10511626757,30158791311,86528621567,248262408987,712297721821,2043676016379
%N Number of (n+2)X(2+2) 0..2 arrays with no row, column, diagonal or antidiagonal in any 3X3 subblock summing to 2 or 4
%C Column 2 of A251682
%H R. H. Hardin, <a href="/A251676/b251676.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) -a(n-2) +12*a(n-3) -29*a(n-4) +a(n-5) -36*a(n-6) +82*a(n-7) +17*a(n-8) +26*a(n-9) -56*a(n-10) -20*a(n-11) -18*a(n-12) -37*a(n-13) -39*a(n-14) +20*a(n-15) +52*a(n-16) +52*a(n-17) +12*a(n-18) -20*a(n-19) -12*a(n-20) -8*a(n-21) for n>22
%e Some solutions for n=4
%e ..1..2..2..2....1..2..2..2....1..2..2..1....0..0..0..1....1..0..0..1
%e ..2..2..1..2....2..2..2..2....2..2..2..2....0..0..1..0....2..0..1..0
%e ..2..2..2..2....2..2..2..2....2..2..2..2....0..1..0..0....0..1..0..0
%e ..2..2..2..2....2..2..2..2....1..2..2..2....1..0..0..1....1..0..0..1
%e ..1..1..1..1....1..2..2..2....2..2..2..2....0..0..1..2....0..0..1..2
%e ..2..2..2..2....2..2..2..2....2..2..2..1....0..1..2..2....0..1..2..0
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 06 2014
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