A296638 Number of nX3 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 1, 2 or 4 neighboring 1s.

4, 28, 132, 671, 3444, 17558, 89613, 457188, 2333009, 11905494, 60751194, 310004765, 1581914211, 8072288131, 41191772847, 210195946958, 1072600980393, 5473335132061, 27929675517731, 142521288635027, 727266512789731

Offset

1,1

Comments

Column 3 of A296643.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -a(n-2) +11*a(n-3) -18*a(n-4) +13*a(n-5) -36*a(n-6) +63*a(n-7) -23*a(n-8) -95*a(n-9) -52*a(n-10) +62*a(n-11) -14*a(n-12) -78*a(n-13) +14*a(n-14) +51*a(n-15) +59*a(n-16) +80*a(n-17) +33*a(n-18) -30*a(n-19) -32*a(n-20) -10*a(n-21) -a(n-22)

Example

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

Crossrefs

Cf. A296643.

Sequence in context: A296381 A240434 A270275 * A270721 A367015 A270892

Adjacent sequences: A296635 A296636 A296637 * A296639 A296640 A296641

Keyword

nonn

Author

R. H. Hardin, Dec 17 2017

Status

approved