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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A236809.

LINKS

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

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

Adjacent sequences:  A236799 A236800 A236801 * A236803 A236804 A236805

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 31 2014

STATUS

approved

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Last modified December 6 15:18 EST 2021. Contains 349563 sequences. (Running on oeis4.)