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A253018 Number of (n+2) X (1+2) 0..3 arrays with every consecutive three elements in every row and column not having exactly two distinct values, and in every diagonal and antidiagonal having exactly two distinct values, and new values 0 upwards introduced in row major order. 1
25, 37, 51, 63, 105, 153, 189, 315, 459, 567, 945, 1377, 1701, 2835, 4131, 5103, 8505, 12393, 15309, 25515, 37179, 45927, 76545, 111537, 137781, 229635, 334611, 413343, 688905, 1003833, 1240029, 2066715, 3011499, 3720087, 6200145, 9034497, 11160261 (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) = 3*a(n-3) for n>5.

Empirical g.f.: x*(25 + 37*x + 51*x^2 - 12*x^3 - 6*x^4) / (1 - 3*x^3). - Colin Barker, Dec 08 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 1 of A253025.

Sequence in context: A079270 A253025 A127022 * A120148 A038516 A080386

Adjacent sequences:  A253015 A253016 A253017 * A253019 A253020 A253021

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 26 2014

STATUS

approved

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Last modified September 17 22:42 EDT 2021. Contains 347489 sequences. (Running on oeis4.)