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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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 26 2014
STATUS
approved

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Last modified June 22 15:57 EDT 2024. Contains 373590 sequences. (Running on oeis4.)