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A204749
Number of (n+2) X 5 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..1 introduced in row major order.
1
102, 31, 22, 27, 35, 48, 69, 103, 158, 247, 391, 624, 1001, 1611, 2598, 4195, 6779, 10960, 17725, 28671, 46382, 75039, 121407, 196432, 317825, 514243, 832054, 1346283, 2178323, 3524592, 5702901, 9227479, 14930366, 24157831, 39088183
OFFSET
1,1
COMMENTS
Column 3 of A204754.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) - a(n-3) for n > 5.
Empirical g.f.: x*(102 - 173*x - 40*x^2 + 85*x^3 + 12*x^4) / ((1 - x)*(1 - x - x^2)). - Colin Barker, Jun 09 2018
EXAMPLE
Some solutions for n=3:
0 0 0 0 0 0 0 0 1 1 0 1 1 1 0 0 0 1 1 1
0 0 0 0 0 1 0 0 0 1 1 1 1 0 0 0 0 0 1 1
1 1 1 1 1 1 1 0 0 0 1 1 0 0 0 1 0 0 0 1
1 1 1 1 1 1 1 1 0 0 1 0 0 0 1 1 1 0 0 0
0 0 0 0 0 0 1 1 1 0 0 0 0 1 1 1 1 1 0 0
CROSSREFS
Cf. A204754.
Sequence in context: A015164 A325776 A325775 * A244949 A266017 A144469
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 18 2012
STATUS
approved