A198280 Number of 2n X 6 0..2 arrays with values 0..2 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors.

2, 14, 100, 662, 4588, 31718, 219060, 1516006, 10490668, 72598710, 502455316, 3477498838, 24068002412, 166577135174, 1152898456372, 7979341139206, 55225944246124, 382225190106390, 2645425190166548, 18309297185224566

Offset

1,1

Comments

Column 3 of A198285.

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -2*a(n-2) -20*a(n-3) -145*a(n-4) +68*a(n-5) +492*a(n-6) +512*a(n-7) +64*a(n-8) -2048*a(n-9).

Empirical g.f.: 2*x*(1 - x - 4*x^2 - 35*x^3 + 31*x^4 + 116*x^5 + 148*x^6 - 576*x^8) / (1 - 8*x + 2*x^2 + 20*x^3 + 145*x^4 - 68*x^5 - 492*x^6 - 512*x^7 - 64*x^8 + 2048*x^9). - Colin Barker, May 14 2018

Example

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

Crossrefs

Cf. A198285.

Sequence in context: A037516 A037719 A158811 * A360319 A074620 A185010

Adjacent sequences: A198277 A198278 A198279 * A198281 A198282 A198283

Keyword

nonn

Author

R. H. Hardin, Oct 23 2011

Status

approved