A183485 - OEIS

A183485

Number of n X 2 0..3 arrays with every element equal to either the sum mod 4 of its vertical neighbors or the sum mod 4 of its horizontal neighbors.

4, 28, 88, 400, 1936, 8368, 38272, 176320, 800512, 3661312, 16761088, 76588288, 350288896, 1602288640, 7327467520, 33513336832, 153280811008, 701043896320, 3206335627264, 14664712241152, 67071268225024, 306761100427264

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OFFSET

1,1

COMMENTS

Column 2 of A183492.

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) + 24*a(n-3) - 48*a(n-4) - 144*a(n-6).

Empirical g.f.: 4*x*(1 + 3*x - 6*x^2 - 12*x^3 - 36*x^4 - 36*x^5) / ((1 - 12*x^3)*(1 - 4*x - 12*x^3)). - Colin Barker, Mar 29 2018

EXAMPLE

Some solutions for 3 X 2.

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

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

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

CROSSREFS

Cf. A183492.

Sequence in context: A030117 A361173 A005634 * A183437 A294315 A263239

Adjacent sequences: A183482 A183483 A183484 * A183486 A183487 A183488

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2011

STATUS

approved