A208318 Number of n X 4 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than two of its immediate leftward or upward or left-upward diagonal neighbors.

14, 982, 71956, 5269968, 385979024, 28269518640, 2070490270512, 151644956050096, 11106641282635568, 813462470412951472, 59578874831184784432, 4363621500998057092272, 319596378043822928054576

Offset

1,1

Comments

Column 4 of A208322.

Links

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

Formula

Empirical: a(n) = 65*a(n-1) + 600*a(n-2) + 320*a(n-3) - 4224*a(n-4) + 1728*a(n-5) for n>6.

Empirical g.f.: 2*x*(7 + 36*x - 137*x^2 - 426*x^3 + 1200*x^4 - 432*x^5) / (1 - 65*x - 600*x^2 - 320*x^3 + 4224*x^4 - 1728*x^5). - Colin Barker, Jul 02 2018

Example

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

Crossrefs

Cf. A208322.

Sequence in context: A064729 A189304 A123178 * A349737 A263217 A208388

Adjacent sequences: A208315 A208316 A208317 * A208319 A208320 A208321

Keyword

nonn

Author

R. H. Hardin, Feb 25 2012

Status

approved