A297079 Number of n X 2 0..1 arrays with no 1 adjacent to 2 king-move neighboring 1s.

4, 12, 30, 96, 286, 848, 2620, 7964, 24332, 74740, 228968, 702656, 2157520, 6622672, 20336808, 62452688, 191784960, 588994592, 1808876976, 5555328528, 17061469024, 52399035584, 160927919584, 494243002176, 1517923151392, 4661861611200

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) + 4*a(n-3) - 14*a(n-4) - 14*a(n-5) - 4*a(n-6).

Empirical g.f.: 2*x*(2 + 2*x - 5*x^2 - 14*x^3 - 9*x^4 - 2*x^5) / (1 - 2*x - 4*x^2 - 4*x^3 + 14*x^4 + 14*x^5 + 4*x^6). - Colin Barker, Feb 26 2019

Example

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

Crossrefs

Column 2 of A297085.

Sequence in context: A324943 A301875 A074252 * A074210 A299053 A005289

Adjacent sequences: A297076 A297077 A297078 * A297080 A297081 A297082

Keyword

nonn

Author

R. H. Hardin, Dec 25 2017

Status

approved