A198901 Number of n X 3 0..4 arrays with values 0..4 introduced in row major order and no element equal to any horizontal or vertical neighbor.

2, 33, 1211, 50384, 2125425, 89793204, 3794115705, 160319061892, 6774239755817, 286243775060868, 12095158053422201, 511077834439270724, 21595464215307153225, 912510860892666556164, 38557914891188891686425

Offset

1,1

Comments

Column 3 of A198906.

Links

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

Formula

Empirical: a(n) = 51*a(n-1) - 393*a(n-2) + 1013*a(n-3) - 902*a(n-4) + 232*a(n-5).

Empirical g.f.: x*(2 - 69*x + 314*x^2 - 434*x^3 + 139*x^4) / ((1 - x)*(1 - 5*x + 2*x^2)*(1 - 45*x + 116*x^2)). - Colin Barker, Mar 02 2018

Example

Some solutions with values 0 to 4 for n=4:
..0..1..2....0..1..2....0..1..2....0..1..0....0..1..0....0..1..0....0..1..2
..1..0..3....1..3..1....2..3..1....1..0..2....2..3..2....2..0..3....2..3..1
..2..1..4....4..1..0....4..0..2....3..4..3....3..2..4....4..2..0....1..4..0
..4..0..3....2..0..2....0..1..3....1..2..1....2..1..0....3..0..4....3..0..4

Crossrefs

Cf. A198906.

Sequence in context: A256278 A356953 A204239 * A242621 A206385 A263052

Adjacent sequences: A198898 A198899 A198900 * A198902 A198903 A198904

Keyword

nonn

Author

R. H. Hardin, Oct 31 2011

Status

approved