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A234154 Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having the absolute values of all six edge and diagonal differences no larger than 1. 1
46, 226, 1108, 5446, 26794, 131896, 649450, 3198322, 15751828, 77581198, 382112002, 1882042264, 9269800642, 45657552106, 224882405380, 1107640064854, 5455593492922, 26871099434488, 132351514215994, 651887143644034 (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) = 7*a(n-1) - 9*a(n-2) - 6*a(n-3).

Empirical g.f.: 2*x*(23 - 48*x - 30*x^2) / (1 - 7*x + 9*x^2 + 6*x^3). - Colin Barker, Oct 13 2018

EXAMPLE

Some solutions for n=5:

  3 3   1 1   2 2   1 2   3 3   3 2   0 1   1 2   2 2   2 2

  2 3   1 0   1 1   2 2   2 3   3 3   0 0   1 2   1 1   2 1

  2 2   0 1   1 0   2 3   2 3   2 3   1 1   2 2   1 2   1 2

  2 1   1 1   1 1   3 3   2 2   3 3   0 0   2 2   2 1   2 2

  1 1   1 1   1 1   3 2   2 3   2 2   1 1   2 2   2 1   1 2

  1 0   1 2   2 1   2 2   3 2   3 3   0 0   2 3   1 2   2 2

CROSSREFS

Column 1 of A234161.

Sequence in context: A083358 A254229 A234161 * A251410 A251403 A026913

Adjacent sequences:  A234151 A234152 A234153 * A234155 A234156 A234157

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 20 2013

STATUS

approved

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Last modified September 19 08:05 EDT 2021. Contains 347556 sequences. (Running on oeis4.)