A296330 Number of n X 3 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 0 or 2 neighboring 1s.

5, 19, 64, 230, 816, 2895, 10277, 36480, 129486, 459622, 1631463, 5790997, 20555577, 72963551, 258989554, 919302704, 3263133386, 11582734875, 41113779717, 145936421820, 518012193480, 1838722844160, 6526683619009, 23166949384421

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 4*a(n-2) + 5*a(n-3) + 2*a(n-4) - 2*a(n-5) - 3*a(n-6) - 2*a(n-7) + a(n-9).

Empirical g.f.: x*(5 + 9*x + 6*x^2 + x^3 - 5*x^4 - 5*x^5 - 2*x^6 + x^7 + x^8) / ((1 + x + x^2)*(1 - 3*x - 2*x^2 + 2*x^5 + x^6 - x^7)). - Colin Barker, Feb 23 2019

Example

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

Crossrefs

Column 3 of A296335.

Sequence in context: A304134 A318946 A229239 * A304162 A001870 A025568

Adjacent sequences: A296327 A296328 A296329 * A296331 A296332 A296333

Keyword

nonn

Author

R. H. Hardin, Dec 10 2017

Status

approved