A230464 Number of n X 3 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero.

0, 0, 114, 1384, 16926, 212124, 2647098, 33046400, 412565142, 5150701380, 64304187186, 802809801448, 10022730288270, 125129422257516, 1562186333636778, 19503215967524816, 243489156724526214

Offset

1,3

Comments

Column 3 of A230469.

Links

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

Formula

Empirical: a(n) = 12*a(n-1) +12*a(n-2) -66*a(n-3) -91*a(n-4) -186*a(n-5) +360*a(n-6) +216*a(n-7).

Empirical g.f.: 2*x^3*(57 + 8*x - 525*x^2 - 36*x^3 + 108*x^4) / (1 - 12*x - 12*x^2 + 66*x^3 + 91*x^4 + 186*x^5 - 360*x^6 - 216*x^7). - Colin Barker, Feb 09 2018

Example

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

Crossrefs

Sequence in context: A262416 A108344 A200551 * A200891 A240386 A220332

Adjacent sequences: A230461 A230462 A230463 * A230465 A230466 A230467

Keyword

nonn

Author

R. H. Hardin, Oct 20 2013

Status

approved