A231376 Number of n X 2 0..1 arrays with no element less than a strict majority of its horizontal and vertical neighbors.

2, 10, 21, 48, 113, 261, 601, 1390, 3216, 7435, 17190, 39751, 91921, 212555, 491510, 1136570, 2628207, 6077470, 14053561, 32497507, 75147355, 173771026, 401828790, 929190453, 2148663614, 4968578109, 11489359399, 26568039511, 61436038272

Offset

1,1

Comments

Column 2 of A231382.

Links

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

Formula

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

Empirical g.f.: x*(2 + 4*x - 5*x^2 + x^3 - 5*x^4 - 2*x^5) / (1 - 3*x + 2*x^2 - 2*x^3 + 2*x^4 + x^5). - Colin Barker, Mar 18 2018

Example

Some solutions for n=3:
..1..0....0..1....0..0....1..0....0..0....1..0....0..0....0..1....0..0....0..0
..1..0....0..0....1..1....0..0....0..0....1..0....0..1....0..1....0..0....1..1
..0..0....0..0....1..1....0..0....0..0....1..0....0..1....0..1....1..1....0..0

Crossrefs

Cf. A231382.

Sequence in context: A294549 A294550 A296555 * A304700 A318548 A318210

Adjacent sequences: A231373 A231374 A231375 * A231377 A231378 A231379

Keyword

nonn

Author

R. H. Hardin, Nov 08 2013

Status

approved