A230782 Number of n X 2 0..3 arrays x(i,j) with each element horizontally, vertically, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, and upper left element zero.

0, 6, 86, 820, 8154, 82576, 833986, 8417644, 84971714, 857764344, 8658840234, 87407976260, 882353220314, 8907050256960, 89913587800402, 907646529844380, 9162377384021426, 92491026597941000, 933664882212237754

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 10*a(n-1) - 3*a(n-2) + 44*a(n-3) - 40*a(n-4) + 8*a(n-5) - 192*a(n-6).

Empirical g.f.: 2*x^2*(3 + 13*x - 11*x^2 - 26*x^3 - 24*x^4) / (1 - 10*x + 3*x^2 - 44*x^3 + 40*x^4 - 8*x^5 + 192*x^6). - Colin Barker, Sep 22 2018

Example

Some solutions for n=3:
..0..3....0..1....0..3....0..2....0..3....0..1....0..2....0..0....0..2....0..3
..0..1....2..1....2..1....1..3....3..1....1..2....3..1....3..1....3..1....3..1
..3..2....0..3....0..3....1..2....2..0....3..0....2..0....0..2....0..3....2..1

Crossrefs

Column 2 of A230787.

Sequence in context: A358297 A209035 A384981 * A318042 A155654 A231165

Adjacent sequences: A230779 A230780 A230781 * A230783 A230784 A230785

Keyword

nonn

Author

R. H. Hardin, Oct 30 2013

Status

approved