A295248 Number of nX3 0..1 arrays with each 1 horizontally or vertically adjacent to 0, 1 or 3 1s.

7, 35, 183, 948, 4928, 25596, 132993, 690938, 3589717, 18649981, 96894136, 503403630, 2615382795, 13587956889, 70594857262, 366768447408, 1905508409402, 9899876400759, 51433807521668, 267219149917538, 1388310092601527

Offset

1,1

Comments

Column 3 of A295253.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +6*a(n-2) +a(n-3) +2*a(n-4) -6*a(n-5) -6*a(n-6) -18*a(n-7) -5*a(n-8) +3*a(n-9) +4*a(n-11) +a(n-12) +9*a(n-13) -a(n-14) +3*a(n-15) -3*a(n-16) -a(n-18)

Example

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

Crossrefs

Cf. A295253.

Sequence in context: A051926 A297602 A289991 * A295647 A026128 A026157

Adjacent sequences: A295245 A295246 A295247 * A295249 A295250 A295251

Keyword

nonn

Author

R. H. Hardin, Nov 18 2017

Status

approved