A296391 Number of nX3 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 1 or 3 neighboring 1s.

3, 11, 36, 115, 387, 1280, 4237, 14026, 46454, 153800, 509255, 1686210, 5583282, 18486920, 61212645, 202682982, 671109638, 2222130975, 7357763936, 24362510288, 80667430752, 267100323021, 884403804216, 2928375674093, 9696231573791

Offset

1,1

Comments

Column 3 of A296396.

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) +2*a(n-3) -3*a(n-4) -2*a(n-5) +7*a(n-6) +4*a(n-7) +a(n-8) -14*a(n-9) +10*a(n-11) -3*a(n-12) -2*a(n-13) +a(n-14)

Example

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

Crossrefs

Cf. A296396.

Sequence in context: A297577 A119126 A119088 * A305132 A291413 A347829

Adjacent sequences: A296388 A296389 A296390 * A296392 A296393 A296394

Keyword

nonn

Author

R. H. Hardin, Dec 11 2017

Status

approved