|
|
A221226
|
|
Number of n X 2 arrays of occupancy after each element moves to some king-move neighbor, with no occupancy greater than 2.
|
|
2
|
|
|
1, 19, 137, 1033, 7877, 60223, 460713, 3524857, 26968225, 206327811, 1578551849, 12076946305, 92396113725, 706885768959, 5408092980713, 41375064828945, 316543208763529, 2421738125898019, 18527690050695513, 141747473284341977
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 15*a(n-1) - 71*a(n-2) + 123*a(n-3) - 78*a(n-4) + 14*a(n-5) - 12*a(n-6) + 8*a(n-7).
Empirical g.f.: x*(1 + 4*x - 77*x^2 + 204*x^3 - 150*x^4 + 28*x^5 + 8*x^6) / (1 - 15*x + 71*x^2 - 123*x^3 + 78*x^4 - 14*x^5 + 12*x^6 - 8*x^7). - Colin Barker, Mar 14 2018
|
|
EXAMPLE
|
Some solutions for n=3:
..0..2....1..2....1..1....2..1....2..2....1..2....0..1....1..1....0..0....1..0
..2..0....0..1....0..2....0..2....1..1....0..2....1..1....1..0....2..2....1..2
..1..1....1..1....1..1....0..1....0..0....1..0....1..2....2..1....0..2....0..2
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|