A230170 Number of n X 2 0..2 arrays x(i,j) with each element horizontally, vertically, diagonally or antidiagonally next to at least one element with value 2-x(i,j).

3, 27, 193, 1407, 10211, 73417, 530771, 3841171, 27770777, 200748959, 1451396131, 10493696945, 75868350707, 548518150083, 3965728577777, 28671821546207, 207294285260867, 1498715914818009, 10835559670997043, 78339967436748115

Offset

1,1

Links

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

Formula

Empirical: a(n) = 6*a(n-1) - 2*a(n-2) + 67*a(n-3) + 62*a(n-4) + 160*a(n-5) + 40*a(n-6) + 16*a(n-7).

Empirical g.f.: x*(1 - x + 11*x^2 - 2*x^3)*(3 + 12*x + 16*x^2 - 8*x^3) / (1 - 6*x + 2*x^2 - 67*x^3 - 62*x^4 - 160*x^5 - 40*x^6 - 16*x^7). - Colin Barker, Sep 21 2018

Example

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

Crossrefs

Column 2 of A230176.

Sequence in context: A145241 A118996 A267947 * A043023 A198686 A357662

Adjacent sequences: A230167 A230168 A230169 * A230171 A230172 A230173

Keyword

nonn

Author

R. H. Hardin, Oct 11 2013

Status

approved