A297339 Number of 2 X n 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 0 or 2 neighboring 1s.

4, 8, 22, 53, 134, 333, 833, 2078, 5190, 12956, 32349, 80764, 201645, 503445, 1256952, 3138228, 7835210, 19562153, 48840794, 121940721, 304449181, 760117722, 1897784554, 4738195288, 11829843673, 29535549464, 73741353337, 184109904521

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 3*a(n-2) + 2*a(n-3) - a(n-5).

Empirical g.f.: x*(4 + 4*x + 2*x^2 - x^3 - x^4) / ((1 + x)*(1 - 2*x - x^2 - x^3 + x^4)). - Colin Barker, Feb 27 2019

Example

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

Crossrefs

Row 2 of A297338.

Sequence in context: A190795 A052528 A058855 * A290138 A266922 A284778

Adjacent sequences: A297336 A297337 A297338 * A297340 A297341 A297342

Keyword

nonn

Author

R. H. Hardin, Dec 28 2017

Status

approved