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A205186
Number of (n+1) X (n+1) 0..1 arrays with the number of clockwise edge increases in every 2 X 2 subblock differing from each horizontal or vertical neighbor.
0
16, 40, 124, 256, 736, 1408, 3904, 7168, 19456, 34816, 93184, 163840, 434176, 753664, 1982464, 3407872, 8912896, 15204352, 39583744, 67108864, 174063616, 293601280, 759169024, 1275068416, 3288334336
OFFSET
1,1
COMMENTS
Diagonal of A205193.
FORMULA
Conjectures from Colin Barker, Jan 17 2018: (Start)
G.f.: 4*x*(4 + 10*x - x^2 - 16*x^3) / ((1 - 2*x)^2*(1 + 2*x)^2).
a(n) = 8*a(n-2) - 16*a(n-4) for n>3.
(End)
EXAMPLE
Some solutions for n=4:
0 0 1 0 1 0 0 1 1 0 0 1 0 0 0 1 0 1 0 0
0 0 0 1 1 0 0 1 1 0 1 0 0 0 1 1 1 0 0 0
1 0 0 1 1 1 1 0 0 1 0 0 0 1 0 1 1 0 0 1
0 1 1 0 0 1 1 0 0 0 0 0 1 0 0 1 0 1 1 0
0 1 1 0 0 0 0 1 0 0 0 1 0 0 0 0 1 1 1 0
CROSSREFS
Sequence in context: A185790 A185761 A205248 * A197903 A300901 A174086
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 23 2012
STATUS
approved