A295374 Number of n X 3 0..1 arrays with each 1 horizontally or vertically adjacent to 0, 2 or 4 1s.

5, 19, 74, 278, 1067, 4071, 15557, 59407, 226944, 866828, 3311093, 12647369, 48309585, 184528995, 704849914, 2692330642, 10283957167, 39281862695, 150045822457, 573133422103, 2189210714608, 8362177726832, 31941199613977

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 4*a(n-2) - 3*a(n-3) + a(n-4) - 8*a(n-5) - 3*a(n-6) + 5*a(n-7) - 2*a(n-8) + a(n-9) + a(n-10).

Empirical g.f.: x*(5 + 4*x - 3*x^2 - 5*x^3 - 11*x^4 + x^5 + 3*x^6 - x^7 + 2*x^8 + x^9) / (1 - 3*x - 4*x^2 + 3*x^3 - x^4 + 8*x^5 + 3*x^6 - 5*x^7 + 2*x^8 - x^9 - x^10). - Colin Barker, Feb 22 2019

Example

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

Crossrefs

Column 3 of A295379.

Sequence in context: A124464 A149766 A254686 * A212403 A098913 A126392

Adjacent sequences: A295371 A295372 A295373 * A295375 A295376 A295377

Keyword

nonn

Author

R. H. Hardin, Nov 21 2017

Status

approved