login
A234138
Number of (n+1) X (6+1) 0..3 arrays with every 2 X 2 subblock having the sum of the absolute values of all six edge and diagonal differences equal to 9.
1
3584, 4040, 4808, 6440, 9512, 16424, 30632, 65192, 141224, 342440, 807848, 2131880, 5299112, 14779304, 37923752, 109378472, 285821864, 840035240, 2216856488, 6581111720, 17457023912, 52093750184, 138546908072, 414532438952
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) + 8*a(n-2) - 30*a(n-3) + 4*a(n-4) + 48*a(n-5) - 32*a(n-6).
Empirical g.f.: 8*x*(448 - 839*x - 4498*x^2 + 8402*x^3 + 7324*x^4 - 13448*x^5) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)*(1 - 8*x^2)). - Colin Barker, Oct 13 2018
EXAMPLE
Some solutions for n=5:
0 3 3 0 3 0 3 0 0 1 3 3 0 3 3 3 0 0 3 3 3
0 0 3 3 3 3 3 0 3 1 0 3 3 3 0 3 3 0 0 3 0
3 0 0 3 0 3 0 0 0 1 3 3 0 3 3 3 0 0 3 3 3
0 0 3 3 3 3 3 0 3 1 0 3 3 3 3 0 0 3 3 0 3
3 0 0 3 0 3 0 0 0 1 3 3 0 3 3 3 0 0 3 3 3
3 3 0 0 0 0 0 0 3 1 0 3 3 3 0 3 3 0 0 3 0
CROSSREFS
Column 6 of A234140.
Sequence in context: A004972 A246855 A252153 * A249289 A249537 A156845
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 19 2013
STATUS
approved