|
|
A304128
|
|
Number of nX3 0..1 arrays with every element unequal to 0, 1, 3 or 6 king-move adjacent elements, with upper left element zero.
|
|
1
|
|
|
3, 7, 9, 19, 33, 53, 89, 155, 261, 439, 749, 1271, 2149, 3647, 6189, 10487, 17781, 30159, 51133, 86695, 147013, 249279, 422669, 716695, 1215253, 2060591, 3493981, 5924487, 10045669, 17033631, 28882605, 48973943, 83041205, 140806415, 238754301
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = a(n-1) +2*a(n-3) for n>7
|
|
EXAMPLE
|
Some solutions for n=5
..0..1..1. .0..0..1. .0..0..0. .0..1..1. .0..0..1. .0..1..1. .0..0..1
..1..1..1. .0..1..1. .0..0..1. .1..1..1. .0..0..0. .0..0..1. .0..1..1
..1..1..1. .0..0..0. .0..1..1. .1..1..1. .0..0..0. .0..0..0. .1..1..1
..1..1..0. .0..0..1. .1..1..1. .0..1..1. .0..0..0. .0..1..1. .1..1..1
..1..0..0. .0..1..1. .1..1..1. .0..0..1. .0..0..0. .0..0..1. .1..1..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|