OFFSET
1,1
COMMENTS
Row 2 of A200553.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-1) -a(n-2) +2*a(n-3) -4*a(n-4) +2*a(n-5) -a(n-6) +2*a(n-7) -a(n-8).
Empirical g.f.: 2*x*(7 + 24*x + 31*x^2 + 47*x^3 + 24*x^4 + 9*x^5 + 2*x^6) / ((1 - x)^4*(1 + x + x^2)^2). - Colin Barker, May 21 2018
EXAMPLE
Some solutions for n=3:
.-2....2....2...-1....2...-3...-2...-2....1...-3....0...-1....1....2...-2....2
..1...-3...-2....0...-1....3...-1....1....0....3...-1...-1...-2...-2...-1....1
..2....1....0...-1....0....2....3...-2....1...-1....2....1....0...-3....2...-3
.-1....0....0....2...-1...-2....0....3...-2....1...-1....1....1....3....1....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 19 2011
STATUS
approved