A230393 Number of n X 2 0..4 arrays x(i,j) with each element horizontally or vertically next to at least one element with value (x(i,j)+1) mod 5, and upper left element zero.

0, 0, 0, 0, 2, 8, 32, 120, 430, 1508, 5216, 17872, 60866, 206448, 698312, 2357640, 7949742, 26782492, 90175912, 303496048, 1021160706, 3435198296, 11554530832, 38860960600, 130691626574, 439504634068, 1477972726608, 4970048569744

Offset

1,5

Comments

Column 2 of A230398.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - 4*a(n-3) - 9*a(n-4) - 6*a(n-5).

Empirical g.f.: 2*x^5 / (1 - 4*x + 4*x^3 + 9*x^4 + 6*x^5). - Colin Barker, Mar 17 2018

Example

Some solutions for n=7:
..0..1....0..1....0..4....0..1....0..4....0..4....0..1....0..1....0..4....0..1
..4..2....3..2....1..2....1..2....1..3....1..3....4..2....3..2....1..3....4..2
..3..3....4..1....2..3....2..3....2..2....2..2....3..3....4..3....2..2....3..3
..2..4....0..0....1..4....1..4....3..1....3..1....2..4....0..2....3..1....2..4
..1..0....1..4....0..0....0..0....4..0....4..0....1..0....1..1....4..0....1..0
..0..4....2..3....4..1....4..1....3..2....3..4....1..4....2..0....3..4....0..4
..2..3....1..0....3..2....3..2....0..1....2..1....2..3....3..4....2..3....4..3

Crossrefs

Cf. A230398.

Sequence in context: A289451 A230509 A099752 * A230529 A282879 A217665

Adjacent sequences: A230390 A230391 A230392 * A230394 A230395 A230396

Keyword

nonn

Author

R. H. Hardin, Oct 18 2013

Status

approved