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A232060 Number of n X 3 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or vertically, with no adjacent values equal. 1
4, 14, 46, 130, 410, 1194, 3722, 10942, 33806, 100142, 307418, 915594, 2797794, 8365310, 25477518, 76390718, 232103802, 697334282, 2115143362, 6363967678, 19279364750, 58067541662, 175757663194, 529761502474, 1602452666114 (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) = 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).

Empirical g.f.: 2*x*(1 + x + x^2)*(2 + 3*x - 3*x^2 - x^3 - 2*x^4 + 2*x^5) / (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 03 2018

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

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

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

CROSSREFS

Column 3 of A232065.

Sequence in context: A255678 A153480 A229007 * A302238 A171851 A117916

Adjacent sequences:  A232057 A232058 A232059 * A232061 A232062 A232063

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 17 2013

STATUS

approved

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Last modified May 7 10:18 EDT 2021. Contains 343650 sequences. (Running on oeis4.)