|
|
A220971
|
|
Equals one maps: number of n X 2 binary arrays indicating the locations of corresponding elements equal to exactly one of their king-move neighbors in a random 0..1 n X 2 array.
|
|
1
|
|
|
2, 2, 9, 23, 58, 149, 379, 969, 2472, 6304, 16057, 40876, 104003, 264525, 672599, 1709802, 4345654, 11043371, 28060714, 71294653, 181127587, 460138081, 1168887760, 2969221064, 7542242881, 19157959588, 48662085275, 123602270581
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 4*a(n-1) - 4*a(n-2) + 3*a(n-3) - 5*a(n-4) - 3*a(n-5) + 6*a(n-6) - 8*a(n-7) for n>10.
Empirical g.f.: x*(2 - 6*x + 9*x^2 - 11*x^3 + 6*x^4 - 2*x^5 - 15*x^6 + 21*x^7 - 14*x^8 + 8*x^9) / ((1 + x)*(1 - 2*x)*(1 - 3*x + 3*x^2 - 6*x^3 + 5*x^4 - 4*x^5)). - Colin Barker, Aug 03 2018
|
|
EXAMPLE
|
All solutions for n=3:
..1..1....0..0....0..0....1..1....0..0....1..1....1..1....0..0....1..1
..1..1....1..0....0..1....1..0....0..0....0..0....0..0....0..0....0..1
..1..1....1..1....1..1....0..0....1..1....0..0....1..1....0..0....0..0
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|