A198599 Number of 2nX6 0..3 arrays with values 0..3 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors

2, 32, 674, 14396, 309770, 6671450, 143724590, 3096625676, 66720604082, 1437592096184, 30975107870150, 667406503209962, 14380307969705594, 309846066281809304, 6676114885818492290, 143847269049688259540

Offset

1,1

Comments

Column 3 of A198604

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 27*a(n-1) -107*a(n-2) -164*a(n-3) -1701*a(n-4) +7073*a(n-5) +13206*a(n-6) +22329*a(n-7) -67473*a(n-8) -190188*a(n-9) -20655*a(n-10) +60507*a(n-11) +177147*a(n-12)

Example

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

Crossrefs

Sequence in context: A038394 A068110 A304860 * A009517 A354382 A202408

Adjacent sequences: A198596 A198597 A198598 * A198600 A198601 A198602

Keyword

nonn

Author

R. H. Hardin Oct 27 2011

Status

approved