A300460 Number of nX3 0..1 arrays with every element equal to 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

0, 2, 2, 8, 22, 68, 212, 652, 2017, 6225, 19229, 59393, 183451, 566633, 1750167, 5405795, 16697038, 51572664, 159294072, 492016422, 1519706056, 4693962286, 14498384074, 44781599826, 138318289075, 427227905079, 1319591820767

Offset

1,2

Comments

Column 3 of A300465.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +2*a(n-2) +3*a(n-3) +a(n-4) +8*a(n-5) +4*a(n-6) -5*a(n-7) -11*a(n-8) +6*a(n-9) -2*a(n-10) -7*a(n-11) -a(n-12) +4*a(n-13) -4*a(n-14) +a(n-15)

Example

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

Crossrefs

Cf. A300465.

Sequence in context: A377243 A130102 A151384 * A377239 A290613 A113464

Adjacent sequences: A300457 A300458 A300459 * A300461 A300462 A300463

Keyword

nonn

Author

R. H. Hardin, Mar 06 2018

Status

approved