A302724 Number of nX3 0..1 arrays with every element equal to 1, 2, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

1, 7, 22, 83, 301, 1079, 4064, 15183, 55012, 207349, 770421, 2830250, 10617371, 39400644, 145704104, 544623685, 2020998479, 7497256552, 27957348859, 103787074017, 385563034716, 1435728019366, 5332352333196, 19821039046245

Offset

1,2

Comments

Column 3 of A302728.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +5*a(n-2) +27*a(n-3) -64*a(n-4) -67*a(n-5) +25*a(n-6) -22*a(n-7) -66*a(n-8) -240*a(n-9) +232*a(n-10) +168*a(n-11) -16*a(n-12) +64*a(n-13) +64*a(n-14) +256*a(n-15) -256*a(n-16)

Example

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

Crossrefs

Cf. A302728.

Sequence in context: A282035 A302273 A151822 * A305083 A231214 A041913

Adjacent sequences: A302721 A302722 A302723 * A302725 A302726 A302727

Keyword

nonn

Author

R. H. Hardin, Apr 12 2018

Status

approved