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A232337 Number of 3 X n 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or antidiagonally, with no adjacent elements equal. 1
1, 16, 74, 154, 628, 1470, 5530, 13906, 49150, 130108, 439834, 1208138, 3956136, 11159566, 35718398, 102702256, 323381538, 942724706, 2933702600, 8637532046, 26653534886, 79035941608, 242412919890, 722524675274, 2206433888880 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = a(n-1) + 7*a(n-2) - 3*a(n-3) + 3*a(n-4) - 7*a(n-5) + 2*a(n-6) - 2*a(n-7) + 2*a(n-8) for n>12.

Empirical g.f.: x*(1 + 15*x + 51*x^2 - 29*x^3 + x^4 - 55*x^5 + 14*x^6 - 4*x^7 + 20*x^8 - 2*x^10 - 2*x^11) / (1 - x - 7*x^2 + 3*x^3 - 3*x^4 + 7*x^5 - 2*x^6 + 2*x^7 - 2*x^8). - Colin Barker, Oct 05 2018

EXAMPLE

Some solutions for n=7.

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

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

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

CROSSREFS

Row 3 of A232335.

Sequence in context: A299679 A300311 A058333 * A124894 A126403 A197873

Adjacent sequences:  A232334 A232335 A232336 * A232338 A232339 A232340

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 22 2013

STATUS

approved

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Last modified September 20 10:14 EDT 2021. Contains 347584 sequences. (Running on oeis4.)