|
|
A279523
|
|
Number of n X 2 0..2 arrays with no element equal to a strict majority of its horizontal and vertical neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
|
|
3
|
|
|
0, 4, 46, 384, 2894, 20444, 138944, 918744, 5954690, 38005496, 239638474, 1496190304, 9265675104, 56988880140, 348469302678, 2120061738416, 12841720934726, 77485235860420, 465936438401536, 2793228811996384
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 12*a(n-1) - 36*a(n-2) - 22*a(n-3) + 140*a(n-4) - 48*a(n-5) - 121*a(n-6) + 88*a(n-7) - 16*a(n-8).
Empirical g.f.: 2*x^2*(1 - x)*(2 + x - 11*x^2 + 4*x^3) / (1 - 6*x + 11*x^3 - 4*x^4)^2. - Colin Barker, Feb 26 2018
|
|
EXAMPLE
|
Some solutions for n=4:
..0..1. .0..0. .0..1. .0..0. .0..1. .0..1. .0..1. .0..1. .0..0. .0..1
..2..1. .1..2. .2..0. .1..1. .1..2. .0..2. .0..0. .1..0. .1..1. .2..2
..0..1. .2..0. .1..1. .1..2. .2..2. .2..2. .0..1. .0..0. .2..1. .1..2
..1..2. .2..2. .0..1. .0..0. .0..0. .0..1. .2..1. .1..1. .2..0. .1..0
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|