A297452 Number of n X 3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 0 or 2 neighboring 1s.

5, 25, 92, 390, 1652, 6888, 28971, 121854, 512165, 2153841, 9057847, 38091340, 160192797, 673691652, 2833214557, 11915133080, 50109322975, 210735765317, 886253689076, 3727158731899, 15674645707885, 65920058839981

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-1) - 3*a(n-2) + 4*a(n-3) - 25*a(n-4) + 10*a(n-5) - 7*a(n-6) + 12*a(n-7).

Empirical g.f.: x*(5 - 18*x^2 - 15*x^3 + 3*x^4 + 5*x^5 + 12*x^6) / (1 - 5*x + 3*x^2 - 4*x^3 + 25*x^4 - 10*x^5 + 7*x^6 - 12*x^7). - Colin Barker, Feb 28 2019

Example

Some solutions for n=7:
..1..0..0. .0..0..0. .0..1..0. .0..0..0. .0..1..0. .1..0..1. .1..1..0
..0..0..1. .0..0..1. .0..1..0. .1..0..0. .0..1..0. .1..0..0. .1..1..0
..1..0..0. .0..0..0. .0..0..0. .1..0..0. .1..1..1. .0..0..1. .0..0..0
..1..0..1. .0..0..0. .1..0..1. .1..0..1. .0..0..0. .0..0..1. .0..1..0
..1..0..1. .0..0..0. .1..0..1. .0..0..1. .0..1..0. .1..0..0. .0..0..0
..1..0..1. .0..1..0. .1..0..0. .1..0..1. .0..0..0. .0..0..1. .1..0..1
..1..0..0. .1..1..1. .0..0..1. .0..0..1. .0..1..0. .1..0..1. .0..0..1

Crossrefs

Column 3 of A297457.

Sequence in context: A083090 A224148 A265929 * A147177 A057255 A134140

Adjacent sequences: A297449 A297450 A297451 * A297453 A297454 A297455

Keyword

nonn

Author

R. H. Hardin, Dec 30 2017

Status

approved