A303406 Number of nX3 0..1 arrays with every element equal to 1, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

1, 7, 28, 119, 541, 2327, 10384, 47491, 208616, 938105, 4229023, 18855226, 84609455, 379973132, 1700940358, 7627893865, 34215621269, 153337948168, 687522535009, 3082887354405, 13820286385598, 61963243406462, 277818915171978

Offset

1,2

Comments

Column 3 of A303410.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +7*a(n-2) +35*a(n-3) -36*a(n-4) -151*a(n-5) -97*a(n-6) +34*a(n-7) +258*a(n-8) -724*a(n-9) +256*a(n-10) +1584*a(n-11) -240*a(n-12) -512*a(n-13) -304*a(n-14) +1728*a(n-15) -1344*a(n-16) -1792*a(n-17) +1024*a(n-18)

Example

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

Crossrefs

Cf. A303410.

Sequence in context: A359018 A302523 A290913 * A054626 A220361 A219737

Adjacent sequences: A303403 A303404 A303405 * A303407 A303408 A303409

Keyword

nonn

Author

R. H. Hardin, Apr 23 2018

Status

approved