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A236802
Number of (n+1) X (1+1) 0..2 arrays with the maximum plus the lower median minus the upper median minus the minimum of every 2 X 2 subblock equal.
3
81, 277, 1033, 4183, 17481, 75907, 330433, 1468723, 6479721, 29026267, 128645233, 577868563, 2565424761, 11535912427, 51246733633, 230538193603, 1024408886601, 4609215271387, 20483612959633, 92170773169843, 409632127625241
OFFSET
1,1
COMMENTS
Column 1 of A236809.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) + 20*a(n-2) - 130*a(n-3) + 36*a(n-4) + 600*a(n-5) - 720*a(n-6).
Empirical g.f.: x*(81 - 128*x - 1972*x^2 + 4008*x^3 + 9000*x^4 - 19440*x^5) / ((1 - 2*x)*(1 - 3*x)*(1 - 6*x^2)*(1 - 20*x^2)). - Colin Barker, Feb 24 2018
EXAMPLE
Some solutions for n=5:
1 2 1 2 0 2 0 2 0 2 0 0 0 2 1 1 2 2 2 1
0 0 2 0 1 0 2 1 1 0 0 0 1 1 1 0 2 1 2 2
0 1 1 0 2 0 2 0 2 0 1 1 2 0 1 1 1 1 2 1
1 1 0 0 0 1 1 2 2 1 1 1 1 1 2 1 2 1 2 0
1 2 1 0 2 2 0 2 0 0 2 2 0 2 0 0 2 0 0 1
1 1 0 0 1 0 0 1 2 1 1 1 1 1 0 1 0 1 0 0
CROSSREFS
Cf. A236809.
Sequence in context: A207042 A206087 A236809 * A236875 A236868 A237375
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 31 2014
STATUS
approved