A202797 Number of n X 3 binary arrays with every one adjacent to another one horizontally or vertically.

4, 36, 250, 1718, 11988, 83518, 581518, 4049700, 28202318, 196400270, 1367728548, 9524845126, 66330898142, 461927514284, 3216857242006, 22402152254494, 156008298702684, 1086439775514766, 7565952552767646, 52689195775528564

Offset

1,1

Comments

Column 3 of A202802.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -3*a(n-2) +19*a(n-3) -3*a(n-4) +25*a(n-5) +24*a(n-6) -22*a(n-7) -16*a(n-8).

Empirical g.f.: 2*x*(2 + 4*x + 5*x^2 + 20*x^4 + 7*x^5 - 16*x^6 - 8*x^7) / (1 - 7*x + 3*x^2 - 19*x^3 + 3*x^4 - 25*x^5 - 24*x^6 + 22*x^7 + 16*x^8). - Colin Barker, Jun 01 2018

Example

Some solutions for n=5:
..0..0..0....0..1..0....0..0..1....0..1..1....0..1..1....0..0..1....0..0..0
..1..0..0....1..1..1....0..0..1....0..1..0....0..0..1....0..0..1....1..0..0
..1..0..0....0..0..1....1..0..1....1..0..0....1..1..0....0..1..0....1..1..1
..0..1..1....0..1..0....1..1..1....1..1..1....0..0..0....0..1..1....1..1..1
..0..1..0....0..1..1....0..1..0....0..0..1....0..1..1....0..0..1....0..1..0

Crossrefs

Cf. A202802.

Sequence in context: A295411 A218516 A119579 * A294832 A075144 A183496

Adjacent sequences: A202794 A202795 A202796 * A202798 A202799 A202800

Keyword

nonn

Author

R. H. Hardin, Dec 24 2011

Status

approved