OFFSET
1,1
COMMENTS
Row 2 of A200454.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = a(n-1) +2*a(n-3) -2*a(n-4) +a(n-5) -2*a(n-6) +a(n-7) -2*a(n-8) +2*a(n-9) +a(n-11) -a(n-12).
Empirical g.f.: 2*(1 + x)*(2 + 18*x + 31*x^2 + 65*x^3 + 63*x^4 + 72*x^5 + 52*x^6 + 39*x^7 + 9*x^8 + 9*x^9) / ((1 - x)^4*(1 + x + x^2)^2*(1 + x + x^2 + x^3 + x^4)). - Colin Barker, May 21 2018
EXAMPLE
Some solutions for n=3:
.-2...-3....1...-2....0...-2....2...-1...-2....1....3....1....0...-1...-2....2
..3...-1....0...-3....2...-1...-2....3....0...-3....2...-2....3....0....3...-1
.-3....3....1....2....1....1....1....0....3...-1...-3....3...-3...-1....1....1
..2....1...-2....3...-3....2...-1...-2...-1....3...-2...-2....0....2...-2...-2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 18 2011
STATUS
approved