|
|
A204278
|
|
Number of (n+2) X 4 0..2 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..2 introduced in row major order.
|
|
1
|
|
|
274, 622, 865, 193, 539, 735, 1883, 5187, 12715, 34507, 94379, 254955, 696107, 1902027, 5190667, 14180299, 38741771, 105832971, 289139339, 789944331, 2158145035, 5896158475, 16108606475, 44009485323, 120236143115, 328491255819
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 3*a(n-1) - 6*a(n-4) + 4*a(n-6) for n > 9.
Empirical g.f.: x*(274 - 200*x - 1001*x^2 - 2402*x^3 + 1604*x^4 + 2850*x^5 + 3772*x^6 - 1792*x^7 - 3072*x^8) / ((1 - x)*(1 - 2*x - 2*x^2)*(1 - 2*x^3)). - Colin Barker, Jun 06 2018
|
|
EXAMPLE
|
Some solutions for n=4:
0 0 1 2 0 1 0 2 0 1 1 0 0 0 0 1 0 0 0 0
0 0 0 1 0 1 0 2 0 1 1 0 0 0 1 1 0 0 0 0
2 0 0 0 0 1 0 2 0 1 1 0 0 1 1 1 1 1 1 1
2 2 0 0 0 1 0 2 0 1 1 0 1 1 1 2 2 2 2 2
2 2 2 0 0 1 0 2 0 1 1 0 1 1 2 2 1 1 1 1
1 2 2 2 0 1 0 2 0 1 1 0 1 2 2 2 1 1 1 1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|