A198522 Number of n X 2 0..4 arrays with values 0..4 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors.

2, 15, 193, 3660, 81844, 1948672, 47436498, 1163606279, 28617909415, 704465305625, 17346617064022, 427184684002131, 10520398796919219, 259092051772297458, 6380839372392481249, 157145577058895542027

Offset

1,1

Comments

Column 2 of A198528.

Links

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

Formula

Empirical: a(n) = 35*a(n-1) -267*a(n-2) +246*a(n-3) +924*a(n-4) +710*a(n-5) -1736*a(n-6) -1860*a(n-7) +72*a(n-8) +1984*a(n-9) +720*a(n-10) -320*a(n-11) -512*a(n-12) for n > 14.

Example

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

Crossrefs

Cf. A198528.

Sequence in context: A349292 A328121 A127090 * A187655 A046249 A042355

Adjacent sequences: A198519 A198520 A198521 * A198523 A198524 A198525

Keyword

nonn

Author

R. H. Hardin Oct 26 2011

Status

approved