|
|
A317768
|
|
Number of nX3 0..1 arrays with every element unequal to 0, 1 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
|
|
1
|
|
|
3, 4, 5, 11, 16, 28, 44, 74, 122, 209, 344, 584, 981, 1670, 2806, 4758, 8047, 13665, 23111, 39195, 66419, 112700, 190989, 323943, 549302, 931821, 1580102, 2680148, 4545629, 7710521, 13077362, 22181756, 37623572, 63817667, 108244170, 183603356
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = a(n-1) +6*a(n-4) -2*a(n-5) -11*a(n-8) -3*a(n-9) +6*a(n-12) +4*a(n-13) -a(n-16) -a(n-17) for n>23
|
|
EXAMPLE
|
Some solutions for n=5
..0..0..0. .0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..1..0. .0..0..0
..0..0..0. .0..0..0. .0..0..1. .1..0..0. .1..0..1. .0..1..1. .0..0..0
..0..0..0. .0..0..0. .0..0..0. .1..1..0. .1..0..1. .1..0..0. .0..0..0
..0..0..0. .0..0..0. .1..1..1. .1..1..1. .0..0..0. .0..0..0. .1..0..0
..0..0..0. .0..0..0. .0..1..1. .1..1..1. .0..0..0. .0..0..0. .1..1..0
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|