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A238908 Number of (n+1) X (3+1) 0..2 arrays with no element equal to all horizontal neighbors or equal to all vertical neighbors, and new values 0..2 introduced in row major order. 1
54, 486, 17496, 408726, 10789686, 274834944, 7073353350, 181499433750, 4661259221016, 119679993219366, 3073064486445414, 78906460267708416, 2026077840987433686, 52023421931028414534, 1335801507196609225944 (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) = 22*a(n-1) + 120*a(n-2) - 678*a(n-3) + 522*a(n-4) + 432*a(n-5) - 81*a(n-6).

Empirical g.f.: 54*x*(1 - 13*x + 6*x^2 + 39*x^3 - 9*x^4) / ((1 - 28*x + 60*x^2 - 9*x^3)*(1 + 6*x - 12*x^2 - 9*x^3)). - Colin Barker, Oct 24 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

CROSSREFS

Column 3 of A238912.

Sequence in context: A230921 A239687 A192216 * A233364 A222968 A228016

Adjacent sequences:  A238905 A238906 A238907 * A238909 A238910 A238911

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 07 2014

STATUS

approved

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Last modified May 22 15:13 EDT 2019. Contains 323480 sequences. (Running on oeis4.)