A303249 Number of nX3 0..1 arrays with every element equal to 1, 2, 3, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

1, 14, 49, 250, 1183, 5918, 28680, 141255, 691968, 3391358, 16627204, 81517689, 399591042, 1958997017, 9603668921, 47080079771, 230803211309, 1131476255863, 5546875012244, 27192677194545, 133307748424215, 653519804327678

Offset

1,2

Comments

Column 3 of A303254.

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) +7*a(n-3) -61*a(n-4) -78*a(n-5) +115*a(n-6) +26*a(n-7) -126*a(n-8) -300*a(n-9) +380*a(n-10) -80*a(n-11) +144*a(n-12) -32*a(n-13) +128*a(n-14)

Example

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

Crossrefs

Cf. A303254.

Sequence in context: A084049 A251221 A302467 * A215569 A246973 A156192

Adjacent sequences: A303246 A303247 A303248 * A303250 A303251 A303252

Keyword

nonn

Author

R. H. Hardin, Apr 20 2018

Status

approved