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A233176 Number of 3 X n 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally, diagonally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs). 1
11, 80, 2688, 78336, 2469888, 76447744, 2385772544, 74291609600, 2315406802944, 72144847372288, 2248141575290880, 70053467808333824, 2182930872087347200, 68021929516908675072, 2119621843032249204736, 66049216835347669843968 (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) = 32*a(n-1) + 64*a(n-2) - 3072*a(n-3) + 8192*a(n-4) for n>5.

Empirical g.f.: x*(11 - 272*x - 576*x^2 + 20992*x^3 - 53248*x^4) / ((1 - 8*x)*(1 - 24*x - 256*x^2 + 1024*x^3)). - Colin Barker, Oct 10 2018

EXAMPLE

Some solutions for n=4:

..0..1..0..4....0..1..5..2....0..1..0..2....0..1..0..1....0..1..2..1

..5..1..5..2....5..1..0..4....3..1..5..1....2..1..5..4....5..1..0..4

..0..4..5..2....3..1..0..4....2..1..5..1....5..1..0..1....5..4..5..1

CROSSREFS

Row 3 of A233174.

Sequence in context: A091098 A091115 A024146 * A156847 A119364 A305826

Adjacent sequences:  A233173 A233174 A233175 * A233177 A233178 A233179

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 05 2013

STATUS

approved

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Last modified January 26 18:56 EST 2021. Contains 340442 sequences. (Running on oeis4.)