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A236049 Number of (n+1) X (2+1) 0..2 arrays colored with the difference of the maximum and minimum in each 2 X 2 subblock. 1
292, 1068, 3516, 11656, 38700, 128920, 429252, 1429352, 4757532, 15839544, 52732564, 175561496, 584466876, 1945813896, 6477977380, 21566507704, 71798959308, 239032817336, 795786352324, 2649328064136, 8820125707548 (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) = a(n-1) + 4*a(n-2) + 5*a(n-3) + 21*a(n-4) + 12*a(n-5) + 4*a(n-6) for n>9.

Empirical g.f.: 4*x*(73 + 194*x + 320*x^2 + 602*x^3 + 377*x^4 + 21*x^5 - 142*x^6 - 80*x^7 - 16*x^8) / (1 - x - 4*x^2 - 5*x^3 - 21*x^4 - 12*x^5 - 4*x^6). - Colin Barker, Oct 20 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 2 of A236055.

Sequence in context: A185999 A048956 A043439 * A233755 A233749 A220410

Adjacent sequences:  A236046 A236047 A236048 * A236050 A236051 A236052

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 18 2014

STATUS

approved

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Last modified September 25 20:38 EDT 2020. Contains 337344 sequences. (Running on oeis4.)