A222460 Number of n X 4 0..7 arrays with no entry increasing mod 8 by 7 rightwards or downwards, starting with upper left zero.

343, 556549, 903055069, 1465295106499, 2377584520856755, 3857863258420747009, 6259760185235726701945, 10157072698503130798653535, 16480843155302567299412163919, 26741778775464749134872807556861

Offset: 1

Author

R. H. Hardin, Feb 21 2013

Keywords

• nonn

Comments

Column 4 of A222462.

Examples

			Some solutions for n=3:
..0..4..2..3....0..0..6..3....0..2..0..1....0..0..2..0....0..4..4..6
..0..0..4..1....0..0..4..1....0..0..2..5....0..0..3..4....0..0..1..7
..0..0..4..6....0..0..6..3....0..0..4..2....0..0..6..2....0..0..3..7
		

Links

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

Crossrefs

Cf. A222462.

Formula

Empirical: a(n) = 1689*a(n-1) - 108775*a(n-2) + 1672631*a(n-3).

Empirical g.f.: 7*x*(49 - 3254*x + 50519*x^2) / (1 - 1689*x + 108775*x^2 - 1672631*x^3). - Colin Barker, Mar 15 2018