|
|
A207996
|
|
Number of nX7 0..2 arrays with new values 0..2 introduced in row major order and no element equal to any horizontal or vertical neighbor (colorings ignoring permutations of colors).
|
|
2
|
|
|
32, 729, 17749, 441090, 11045757, 277458045, 6978332618, 175605187731, 4419979346851, 111261280858024, 2800819361992659, 70507189155056781, 1774944424628356230, 44682493917576202087, 1124839588414204665607
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 55*a(n-1) -1109*a(n-2) +11330*a(n-3) -67206*a(n-4) +247404*a(n-5) -582440*a(n-6) +881876*a(n-7) -846764*a(n-8) +499200*a(n-9) -172400*a(n-10) +33152*a(n-11) -3264*a(n-12) +128*a(n-13).
G.f.: -x*(32 -1031*x +13142*x^2 -89204*x^3 +360470*x^4 -909704*x^5 +1454814*x^6 -1461492*x^7 +896144*x^8 -320568*x^9 +63472*x^10 -6400*x^11 +256*x^12) / ( -1 +55*x -1109*x^2 +11330*x^3 -67206*x^4 +247404*x^5 -582440*x^6 +881876*x^7 -846764*x^8 +499200*x^9 -172400*x^10 +33152*x^11 -3264*x^12 +128*x^13 ). - R. J. Mathar, Nov 23 2015
|
|
EXAMPLE
|
Some solutions for n=4
..0..1..0..2..1..2..0....0..1..2..1..2..0..1....0..1..2..1..2..0..1
..2..0..1..0..2..1..2....2..0..1..2..0..2..0....1..2..1..2..0..1..2
..0..1..0..1..0..2..0....0..1..2..1..2..1..2....2..0..2..1..2..0..1
..2..0..2..0..1..0..1....1..0..1..2..1..2..0....0..1..0..2..0..1..2
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|