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A236048 Number of (n+1) X (1+1) 0..2 arrays colored with the difference of the maximum and minimum in each 2 X 2 subblock. 1
81, 292, 1112, 3760, 13716, 46828, 169500, 582300, 2096012, 7237244, 25932972, 89903068, 320993612, 1116363900, 3974561132, 13858016796, 49226653068, 171984277180, 609825727660, 2133983154780, 7555901021900, 26474357927164 (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-2) + 4*a(n-3) + 24*a(n-4) + 12*a(n-5) + 8*a(n-6) for n > 8.

Empirical g.f.: x*(81 + 292*x + 383*x^2 + 808*x^3 + 596*x^4 + 560*x^5 + 176*x^6 + 64*x^7) / (1 - 9*x^2 - 4*x^3 - 24*x^4 - 12*x^5 - 8*x^6). - Colin Barker, Oct 20 2018

EXAMPLE

Some solutions for n=4:

  2 2   2 1   0 1   1 1   1 2   2 2   1 0   0 0   2 2   1 0

  2 2   2 2   0 1   1 1   2 1   1 1   0 1   1 2   1 1   2 2

  2 1   1 0   1 2   0 0   1 0   1 1   2 2   2 1   1 1   2 1

  0 1   0 0   2 1   0 0   0 0   0 0   1 2   0 0   1 2   0 1

  0 0   0 2   0 0   1 2   0 2   2 1   0 0   0 1   0 1   1 0

CROSSREFS

Column 1 of A236055.

Sequence in context: A237368 A017078 A236055 * A235954 A235947 A237809

Adjacent sequences:  A236045 A236046 A236047 * A236049 A236050 A236051

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 18 2014

STATUS

approved

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Last modified April 22 22:22 EDT 2019. Contains 322378 sequences. (Running on oeis4.)