A195964 - OEIS

A195964

Number of n X 3 0..4 arrays with each element equal to the number its horizontal and vertical neighbors equal to itself.

2, 2, 5, 7, 14, 25, 35, 56, 107, 173, 284, 491, 805, 1338, 2299, 3817, 6348, 10741, 17955, 29996, 50517, 84551, 141438, 237601, 398131, 666648, 1118507, 1874589, 3140516, 5266459, 8827461, 14792378, 24799555, 41569097, 69668012, 116786117, 195757315

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OFFSET

1,1

COMMENTS

Column 3 of A195969.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 2*a(n-3) +2*a(n-4) +2*a(n-5) +4*a(n-6) -a(n-9) for n>11.

Empirical g.f.: x*(2 + 2*x + 5*x^2 + 3*x^3 + 6*x^4 + 7*x^5 - x^6 - 4*x^7 - 5*x^8 - x^9 - 2*x^10) / (1 - 2*x^3 - 2*x^4 - 2*x^5 - 4*x^6 + x^9). - Colin Barker, May 08 2018

EXAMPLE

All solutions for n=4:

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

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

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

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

CROSSREFS

Cf. A195969.

Sequence in context: A259864 A028303 A255063 * A375079 A238422 A047083

Adjacent sequences: A195961 A195962 A195963 * A195965 A195966 A195967

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 25 2011

STATUS

approved