A281558 Number of nX3 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 5, 68, 815, 4172, 18020, 62882, 201551, 605398, 1743548, 4863258, 13228596, 35268263, 92503663, 239307757, 611896213, 1548973531, 3887082301, 9679914966, 23942689688, 58864085078, 143936487738, 350238677040, 848456244849

Offset

1,2

Comments

Column 3 of A281563.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -12*a(n-2) +17*a(n-3) -45*a(n-4) +60*a(n-5) -3*a(n-6) +33*a(n-8) -255*a(n-9) +303*a(n-10) -195*a(n-11) +105*a(n-12) +96*a(n-13) -348*a(n-14) +644*a(n-15) -528*a(n-16) +48*a(n-17) +304*a(n-18) -384*a(n-19) +192*a(n-20) -64*a(n-21) for n>29

Example

Some solutions for n=4
..0..1..1. .0..1..1. .0..0..1. .0..1..1. .0..0..1. .0..1..1. .0..0..1
..1..0..1. .1..1..0. .1..0..0. .1..0..1. .1..1..1. .1..0..0. .0..0..0
..1..1..1. .1..0..0. .1..1..0. .1..1..1. .1..0..1. .1..0..0. .0..1..1
..1..0..0. .1..0..0. .0..0..0. .1..0..1. .1..1..0. .1..1..0. .0..0..1

Crossrefs

Cf. A281563.

Sequence in context: A363401 A336433 A099334 * A165396 A029812 A208562

Adjacent sequences: A281555 A281556 A281557 * A281559 A281560 A281561

Keyword

nonn

Author

R. H. Hardin, Jan 24 2017

Status

approved