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.

81, 277, 1033, 4183, 17481, 75907, 330433, 1468723, 6479721, 29026267, 128645233, 577868563, 2565424761, 11535912427, 51246733633, 230538193603, 1024408886601, 4609215271387, 20483612959633, 92170773169843, 409632127625241

Offset: 1

Author

R. H. Hardin, Jan 31 2014

Keywords

• nonn

Comments

Column 1 of A236809.

Examples

			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
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A236809.

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