|
|
A208562
|
|
Number of n X 3 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward or left-upward diagonal neighbors.
|
|
1
|
|
|
5, 68, 1059, 16608, 260856, 4098492, 64398564, 1011891888, 15899856696, 249834571632, 3925652965344, 61683823050048, 969238512405216, 15229654196873472, 239303704937730624, 3760181449823927808
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 22*a(n-1) - 110*a(n-2) + 180*a(n-3) - 60*a(n-4) for n>5.
Empirical g.f.: x*(5 - 42*x + 113*x^2 - 110*x^3 + 30*x^4) / (1 - 22*x + 110*x^2 - 180*x^3 + 60*x^4). - Colin Barker, Jul 05 2018
|
|
EXAMPLE
|
Some solutions for n=4:
..0..0..0....0..0..1....0..0..0....0..0..0....0..0..1....0..0..1....0..1..2
..1..1..1....2..1..2....0..1..1....0..1..2....2..1..2....2..1..0....1..2..0
..1..0..0....2..0..0....1..2..0....2..0..1....2..0..2....2..0..1....0..1..0
..1..2..2....0..2..1....1..2..1....0..1..0....2..0..1....2..0..2....2..0..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|