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A236886 Number of (n+1) X (1+1) 0..2 arrays with the maximum plus the upper median minus the lower median minus the minimum of every 2 X 2 subblock equal. 1
81, 245, 781, 2605, 8901, 31253, 111685, 406949, 1503365, 5632837, 21327109, 81569413, 314366469, 1220142341, 4761187333, 18668554757, 73468028933, 290057876485, 1147984105477, 4553121130501, 18087737270277, 71955008016389 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 9*a(n-1) - 8*a(n-2) - 136*a(n-3) + 364*a(n-4) + 380*a(n-5) - 2080*a(n-6) + 992*a(n-7) + 2400*a(n-8) - 1920*a(n-9).

Empirical g.f.: x*(81 - 484*x - 776*x^2 + 8552*x^3 - 4460*x^4 - 41760*x^5 + 46992*x^6 + 46592*x^7 - 58112*x^8) / ((1 - x)*(1 - 2*x)*(1 - 4*x)*(1 - 2*x - 4*x^2)*(1 - 6*x^2)*(1 - 10*x^2)). - Colin Barker, Oct 21 2018

EXAMPLE

Some solutions for n=5:

..2..0....2..1....1..1....2..2....2..0....2..2....1..2....1..2....2..1....0..1

..0..1....0..2....2..0....1..0....2..1....2..1....2..0....0..1....0..2....1..2

..0..2....1..0....0..0....2..0....0..0....1..1....0..1....1..0....1..2....1..0

..2..1....2..0....0..2....1..0....1..2....2..1....2..0....1..0....2..0....1..0

..0..2....1..2....0..0....2..2....0..0....2..2....1..0....2..1....2..1....1..2

..2..1....2..0....1..1....1..0....1..2....1..2....2..0....1..0....0..2....2..1

CROSSREFS

Column 1 of A236893.

Sequence in context: A236893 A044986 A237160 * A206142 A225027 A225020

Adjacent sequences:  A236883 A236884 A236885 * A236887 A236888 A236889

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 01 2014

STATUS

approved

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Last modified March 31 16:23 EDT 2020. Contains 333151 sequences. (Running on oeis4.)