|
|
A206407
|
|
Number of (n+1) X 2 0..2 arrays with every 2 X 3 or 3 X 2 subblock having an equal number of clockwise and counterclockwise edge increases.
|
|
1
|
|
|
81, 423, 2457, 15087, 94761, 600519, 3818649, 24314127, 154889673, 986887623, 6288452889, 40071132591, 255342940521, 1627113214023, 10368413881497, 66070427765967, 421019298884361, 2682853284675399, 17095895564336409
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 9*a(n-1) - 17*a(n-2) + a(n-3) + 4*a(n-4).
Empirical g.f.: 3*x*(27 - 102*x + 9*x^2 + 28*x^3) / ((1 - 2*x - x^2)*(1 - 7*x + 4*x^2)). - Colin Barker, Jun 16 2018
|
|
EXAMPLE
|
Some solutions for n=4:
1 2 1 2 1 2 0 1 2 0 1 2 1 2 2 1 2 2 1 2
0 0 1 1 0 1 2 0 2 2 1 2 0 2 0 2 0 0 0 1
1 2 1 1 2 0 2 2 2 0 1 2 0 1 1 0 2 2 2 0
0 2 1 0 2 0 0 2 2 2 1 1 0 2 2 1 0 2 2 2
0 1 1 0 0 1 2 0 0 2 2 1 1 2 1 0 2 0 0 0
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|