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A205354
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Number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having the same number of equal diagonal or antidiagonal elements, and new values 0..2 introduced in row major order.
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2
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14, 50, 194, 770, 3074, 12290, 49154, 196610, 786434, 3145730, 12582914, 50331650, 201326594, 805306370, 3221225474, 12884901890, 51539607554, 206158430210, 824633720834, 3298534883330, 13194139533314, 52776558133250
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 5*a(n-1) - 4*a(n-2).
G.f.: 2*x*(7 - 10*x) / ((1 - x)*(1 - 4*x)).
a(n) = 2 + 3*4^n.
(End)
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EXAMPLE
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Some solutions for n=4:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1 2 0 0 0 1 0 1 1 2 1 1 1 2 0 1 0 1 0 0
0 0 0 0 2 0 2 0 1 2 2 2 0 2 0 0 0 0 0 0
1 1 0 0 2 2 1 2 0 0 0 1 0 1 2 0 2 0 0 0
2 0 0 0 1 2 2 2 1 2 2 2 2 2 1 2 2 2 0 0
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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