A295647 Number of nX3 0..1 arrays with each 1 horizontally or vertically adjacent to 0, 1, 3 or 4 1s.

7, 35, 184, 956, 4993, 26037, 135848, 708695, 3697224, 19288127, 100624816, 524952380, 2738639019, 14287283144, 74535731534, 388847564661, 2028589853186, 10583007752168, 55210792323272, 288030743269151, 1502635727144728

Offset

1,1

Comments

Column 3 of A295652.

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) -9*a(n-3) -a(n-4) -13*a(n-5) -11*a(n-6) -8*a(n-7) +37*a(n-8) +30*a(n-9) -31*a(n-10) +29*a(n-11) -4*a(n-12) +a(n-13) -8*a(n-14) +4*a(n-15) -7*a(n-16) +a(n-17) -a(n-18)

Example

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

Crossrefs

Cf. A295652.

Sequence in context: A297602 A289991 A295248 * A026128 A026157 A025184

Adjacent sequences: A295644 A295645 A295646 * A295648 A295649 A295650

Keyword

nonn

Author

R. H. Hardin, Nov 25 2017

Status

approved