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A268419 Number of n X 1 0..3 arrays with every repeated value in every row unequal to the previous repeated value, and in every column equal to the previous repeated value, and new values introduced in row-major sequential order. 1
1, 2, 5, 14, 44, 147, 505, 1750, 6065, 20950, 72052, 246715, 841345, 2858714, 9682221, 32700942, 110173948, 370393059, 1242869721, 4163561358, 13927246329, 46526402422, 155249799428, 517505902283, 1723457914689, 5734951039346 (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) = 8*a(n-1) - 20*a(n-2) + 12*a(n-3) + 12*a(n-4) - 8*a(n-5) - 3*a(n-6).

Empirical g.f.: x*(1 - 6*x + 9*x^2 + 2*x^3 - 4*x^4 - x^5) / ((1 - x)*(1 - 3*x)*(1 - x - x^2)*(1 - 3*x - x^2)). - Colin Barker, Jan 13 2019

EXAMPLE

Some solutions for n=8:

..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0

..0....1....1....1....0....1....1....1....1....0....1....1....1....1....0....1

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

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

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

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

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

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

CROSSREFS

Column 1 of A268423.

Sequence in context: A137557 A306799 A148335 * A149883 A307786 A149884

Adjacent sequences:  A268416 A268417 A268418 * A268420 A268421 A268422

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 04 2016

STATUS

approved

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Last modified June 28 12:59 EDT 2022. Contains 354907 sequences. (Running on oeis4.)