|
|
A222460
|
|
Number of n X 4 0..7 arrays with no entry increasing mod 8 by 7 rightwards or downwards, starting with upper left zero.
|
|
2
|
|
|
343, 556549, 903055069, 1465295106499, 2377584520856755, 3857863258420747009, 6259760185235726701945, 10157072698503130798653535, 16480843155302567299412163919, 26741778775464749134872807556861
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 1689*a(n-1) - 108775*a(n-2) + 1672631*a(n-3).
Empirical g.f.: 7*x*(49 - 3254*x + 50519*x^2) / (1 - 1689*x + 108775*x^2 - 1672631*x^3). - Colin Barker, Mar 15 2018
|
|
EXAMPLE
|
Some solutions for n=3:
..0..4..2..3....0..0..6..3....0..2..0..1....0..0..2..0....0..4..4..6
..0..0..4..1....0..0..4..1....0..0..2..5....0..0..3..4....0..0..1..7
..0..0..4..6....0..0..6..3....0..0..4..2....0..0..6..2....0..0..3..7
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|