A318019 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

4, 14, 45, 133, 419, 1382, 4495, 14754, 48525, 159584, 524981, 1727658, 5685321, 18710300, 61576790, 202655046, 666960573, 2195053580, 7224214965, 23775889227, 78249787781, 257531127865, 847571571085, 2789478970713, 9180573908293

Offset

1,1

Comments

Column 3 of A318024.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +4*a(n-2) -5*a(n-3) -14*a(n-4) -17*a(n-5) +18*a(n-6) +29*a(n-7) +23*a(n-8) +12*a(n-9) -27*a(n-10) -27*a(n-11) -16*a(n-12) -7*a(n-13) -5*a(n-14) +18*a(n-15) -9*a(n-16) +9*a(n-17) -3*a(n-18) for n>23

Example

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

Crossrefs

Cf. A318024.

Sequence in context: A208666 A125068 A184138 * A182902 A108765 A304068

Adjacent sequences: A318016 A318017 A318018 * A318020 A318021 A318022

Keyword

nonn

Author

R. H. Hardin, Aug 12 2018

Status

approved