|
| |
|
|
A253462
|
|
Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock diagonal maximum minus antidiagonal minimum unequal to its neighbors horizontally, vertically, diagonally and antidiagonally.
|
|
1
|
|
|
|
81, 540, 3640, 24208, 162016, 1081504, 7227096, 48272160, 322493040, 2154281664, 14391427080, 96138251504, 642233318880, 4290297708128, 28660448653048, 191460012669504, 1279008408531440, 8544145042353728, 57077359575083624
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
LINKS
|
|
|
|
FORMULA
|
Empirical: a(n) = 2*a(n-1) + 27*a(n-2) + 30*a(n-3) - 7*a(n-4) - 8*a(n-5) - 75*a(n-6) - 48*a(n-7) - 16*a(n-8).
Empirical g.f.: x*(81 + 378*x + 373*x^2 - 82*x^3 - 313*x^4 - 916*x^5 - 709*x^6 - 156*x^7) / (1 - 2*x - 27*x^2 - 30*x^3 + 7*x^4 + 8*x^5 + 75*x^6 + 48*x^7 + 16*x^8). - Colin Barker, Dec 14 2018
|
|
|
EXAMPLE
|
Some solutions for n=4:
..2..1....0..0....2..1....2..2....0..0....2..1....1..1....2..2....1..0....2..2
..2..2....0..1....2..2....2..0....1..1....1..2....2..1....0..0....1..2....2..0
..0..0....0..2....2..0....0..0....2..1....2..1....2..0....2..0....0..0....1..0
..2..0....1..0....0..2....0..0....0..1....2..2....2..1....2..1....2..0....2..1
..1..1....1..2....1..0....1..1....0..1....0..1....1..2....2..1....2..1....0..1
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
