OFFSET
1,1
COMMENTS
Column 2 of A189951
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: (n+1)*a(n) = 4*(2*n+1)*a(n-1) - 24*n*a(n-2) + 16*(2*n-1)*a(n-3). - Vaclav Kotesovec, Oct 19 2012
EXAMPLE
Some solutions with n=3
..2....2....2....1...-2...-2....1....2....2....1....2...-2...-2...-2...-1...-2
..2....2....2....2....2...-2...-2....2...-2....1....2....2....2...-2....2...-2
..2...-2...-2...-1...-1....1...-1...-1....2...-1...-2....2...-1....2....1...-1
..2...-1...-2....2....1....1....2....1...-2...-1....2...-2...-1....1....2...-1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin May 02 2011
STATUS
approved