A281338 Number of n X 2 0..1 arrays with no element equal to more than three of its king-move neighbors and with new values introduced in order 0 sequentially upwards.

2, 8, 25, 85, 286, 969, 3281, 11114, 37649, 127541, 432062, 1463673, 4958409, 16797346, 56903505, 192769085, 653033942, 2212249593, 7494324497, 25388138778, 86006095793, 291358440197, 987020046574, 3343677195961, 11327203768153

Offset

1,1

Comments

Column 2 of A281344.

Links

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

Formula

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

Empirical g.f.: x*(2 + 2*x - x^2 - 2*x^3 - 6*x^4) / (1 - 3*x - x^2 - 2*x^3 + 2*x^4 + 4*x^5). - Colin Barker, Feb 21 2018

Example

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

Crossrefs

Cf. A281344.

Sequence in context: A301842 A240478 A288539 * A036367 A115256 A132963

Adjacent sequences: A281335 A281336 A281337 * A281339 A281340 A281341

Keyword

nonn

Author

R. H. Hardin, Jan 20 2017

Status

approved