|
|
A221021
|
|
Equals one maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal, vertical and antidiagonal neighbors in a random 0..3 nX3 array
|
|
1
|
|
|
4, 38, 371, 3474, 30167, 251674, 2055232, 16609480, 133546783, 1071058030, 8579199454, 68676536212, 549584051869, 4397359463098, 35181623896924, 281463983943136, 2251755842615323, 18014222625202438, 144114484538737882
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 12*a(n-1) -30*a(n-2) -24*a(n-3) +63*a(n-4) +12*a(n-5) -32*a(n-6) for n>11
|
|
EXAMPLE
|
Some solutions for n=3
..1..1..0....1..0..1....0..0..1....0..1..0....1..0..0....1..0..1....0..0..1
..1..0..0....1..0..0....1..1..0....1..0..1....0..0..1....1..0..0....1..0..1
..1..0..1....0..1..0....1..0..0....0..1..0....0..1..0....1..0..0....0..1..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|