|
|
A184606
|
|
Half the number of (n+1) X 2 binary arrays with no 2 X 2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.
|
|
1
|
|
|
8, 28, 98, 350, 1250, 4450, 15842, 56426, 200978, 715786, 2549282, 9079418, 32336882, 115169482, 410182082, 1460885210, 5203020050, 18530830570, 65998531298, 235057255034, 837168828722, 2981620996234, 10619200644098
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 3*a(n-1) + 6*a(n-3) + 4*a(n-4).
Empirical g.f.: 2*x*(4 + 2*x + 7*x^2 + 4*x^3) / ((1 + 2*x^2)*(1 - 3*x - 2*x^2)). - Colin Barker, Apr 14 2018
|
|
EXAMPLE
|
Some solutions for 3 X 2:
..1..1....0..0....1..1....1..0....1..1....1..1....0..1....0..1....0..0....0..1
..0..0....0..1....0..1....0..0....1..0....0..0....0..0....1..1....1..1....1..0
..1..0....1..0....1..0....0..1....1..1....0..1....0..1....1..1....0..1....1..1
...
...2.......1.......3.......1.......3.......2.......1.......3.......2.......2...
...1.......2.......2.......1.......3.......1.......1.......4.......3.......3...
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|