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A237938 Number of (n+1) X (1+1) 0..2 arrays with the maximum minus the minimum of every 2 X 2 subblock equal. 1
81, 437, 2417, 13893, 81245, 482409, 2893685, 17487137, 106223237, 647551889, 3957272037, 24224070993, 148455289413, 910505201009, 5587258627429, 34298159298769, 210595144024709, 1293294251436721, 7943185773864101 (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) = 8*a(n-1) - a(n-2) - 64*a(n-3) - 14*a(n-4) + 88*a(n-5) + 8*a(n-6) - 24*a(n-7).

Empirical g.f.: x*(81 - 211*x - 998*x^2 + 178*x^3 + 1620*x^4 + 20*x^5 - 456*x^6) / ((1 - x)*(1 - 2*x - 8*x^2 - 4*x^3)*(1 - 5*x - 8*x^2 + 6*x^3)). - Colin Barker, Oct 24 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

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

CROSSREFS

Column 1 of A237945.

Sequence in context: A237308 A237301 A237945 * A017630 A270538 A230064

Adjacent sequences:  A237935 A237936 A237937 * A237939 A237940 A237941

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 16 2014

STATUS

approved

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Last modified August 14 02:47 EDT 2022. Contains 356109 sequences. (Running on oeis4.)