A268797 Number of nX7 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two exactly once.

576, 4360, 41248, 561116, 7801688, 104971262, 1384570516, 17967375416, 230262982692, 2921020155826, 36745483472428, 459003330021886, 5699362152372404, 70403795917829390, 865796392149477244

Offset: 1

Author

R. H. Hardin, Feb 13 2016

Keywords

• nonn

Comments

Column 7 of A268798.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210
• R. H. Hardin, Empirical recurrence of order 68

Crossrefs

Cf. A268798.

Formula

Empirical recurrence of order 68 (see link above)