|
|
A252250
|
|
Number of (n+2) X (4+2) 0..3 arrays with every 3 X 3 subblock row and column sum not equal to 0 3 5 6 or 7 and every 3 X 3 diagonal and antidiagonal sum equal to 0 3 5 6 or 7.
|
|
1
|
|
|
352, 268, 249, 267, 297, 336, 384, 462, 564, 690, 894, 1161, 1491, 2025, 2724, 3588, 4986, 6816, 9078, 12738, 17529, 23451, 33033, 45576, 61080, 86166, 119004, 159594, 225270, 311241, 417507, 589449, 814524, 1092732, 1542882, 2132136, 2860494
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = a(n-1) + 3*a(n-3) - 3*a(n-4) - a(n-6) + a(n-7) for n>9.
Empirical g.f.: x*(352 - 84*x - 19*x^2 - 1038*x^3 + 282*x^4 + 96*x^5 + 346*x^6 - 96*x^7 - 34*x^8) / ((1 - x)*(1 - 3*x^3 + x^6)). - Colin Barker, Dec 02 2018
|
|
EXAMPLE
|
Some solutions for n=4:
..3..3..3..3..3..3....0..1..0..1..0..3....0..1..1..0..1..1....3..1..0..0..1..0
..1..0..1..0..1..0....1..0..1..0..1..0....2..3..3..2..3..3....2..0..2..2..0..2
..0..1..0..1..0..1....0..1..0..1..0..1....2..0..0..2..0..0....3..1..0..0..1..0
..1..0..1..0..1..0....1..0..1..0..1..0....0..1..1..0..1..1....3..1..0..0..1..0
..0..1..0..1..0..1....0..1..0..1..0..1....2..3..3..2..3..3....2..0..2..2..0..2
..3..0..1..0..1..3....1..0..1..0..1..3....2..0..0..2..0..0....3..1..0..0..1..0
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|