OFFSET
1,1
COMMENTS
Row 3 of A212729
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
From Vaclav Kotesovec, Jul 31 2013: (Start)
Empirical: n*(2*n-1)*(59040*n^4 - 630664*n^3 + 2419338*n^2 - 3925427*n + 2259783)*a(n) = (2243520*n^6 - 26740112*n^5 + 122386084*n^4 - 271040464*n^3 + 300314759*n^2 - 153351297*n + 26751060)*a(n-1) + 81*(n-3)*(2*n-7)*(59040*n^4 - 394504*n^3 + 881586*n^2 - 742583*n + 182070)*a(n-3) - 9*(1298880*n^6 - 16413328*n^5 + 81293588*n^4 - 199839104*n^3 + 252840847*n^2 - 150974403*n + 30574530)*a(n-2)
Conjecture: a(n) ~ 9/2*9^n. (End)
EXAMPLE
Some solutions for n=3
..2....0....1....1....2....0....0....0....0....1....0....1....1....0....1....0
..0....0....0....0....0....1....0....0....1....1....2....0....0....1....0....2
..0....1....1....0....0....0....1....2....1....0....0....1....0....1....0....1
..2....2....1....2....1....1....0....1....0....1....1....0....0....0....0....0
..0....1....0....0....1....0....1....0....0....1....0....1....2....0....0....0
..0....0....0....0....0....2....0....0....0....0....1....1....0....1....0....0
..0....1....1....1....2....0....0....0....1....0....0....0....0....2....0....2
..2....0....1....0....0....2....2....1....1....2....0....2....1....0....0....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin May 25 2012
STATUS
approved