A232425 Number of (n+1) X (1+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally or vertically.

4, 16, 64, 240, 988, 3964, 15844, 63808, 256096, 1029152, 4133548, 16607836, 66714260, 268019952, 1076703872, 4325480208, 17376731196, 69807805884, 280439281284, 1126611556192, 4525945532832, 18182121542848, 73043190744972

Offset

1,1

Comments

Column 1 of A232431.

Links

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

Formula

Empirical: a(n) = a(n-1) + 10*a(n-2) + 11*a(n-3) - a(n-4) - 28*a(n-5) - 32*a(n-6).

Empirical g.f.: 4*x*(1 + 3*x + 2*x^2 - 7*x^3 - 16*x^4) / (1 - x - 10*x^2 - 11*x^3 + x^4 + 28*x^5 + 32*x^6). - Colin Barker, Mar 19 2018

Example

Some solutions for n=7:
..2..1....2..2....1..2....0..1....1..2....0..1....1..2....0..1....2..1....0..1
..1..0....1..1....0..0....2..2....0..0....2..2....0..1....1..2....1..0....0..2
..2..1....0..0....2..1....1..1....2..1....1..0....1..2....0..1....1..2....1..1
..1..2....0..1....2..2....0..0....1..2....2..1....2..2....1..2....0..0....2..0
..0..1....2..2....1..0....1..2....0..1....1..2....0..1....2..1....2..1....0..1
..0..1....1..1....2..1....0..0....0..0....0..2....1..0....1..0....1..2....1..2
..1..2....0..0....0..1....2..1....1..2....0..1....2..1....2..2....0..2....1..2
..0..1....1..2....1..2....1..0....0..1....1..2....1..0....0..1....0..1....0..1

Crossrefs

Cf. A232431.

Sequence in context: A294037 A228735 A289694 * A180239 A006811 A269685

Adjacent sequences: A232422 A232423 A232424 * A232426 A232427 A232428

Keyword

nonn

Author

R. H. Hardin, Nov 23 2013

Status

approved