OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) + 5*a(n-2) - 7*a(n-3) - 6*a(n-4).
Empirical g.f.: 4*x*(4 + 3*x)*(5 - 9*x^2) / (1 - 4*x - 5*x^2 + 7*x^3 + 6*x^4). - Colin Barker, Oct 12 2018
EXAMPLE
Some solutions for n=5:
..0..1....5..4....1..3....5..4....4..5....4..2....3..2....2..1....1..0....2..1
..2..3....4..2....0..1....3..5....2..4....3..1....5..3....1..3....3..2....4..2
..3..1....2..3....2..0....4..3....4..3....2..0....3..2....3..4....5..3....5..3
..4..3....4..5....3..2....3..1....2..4....3..2....2..0....1..3....4..2....4..5
..2..1....2..3....2..4....4..3....1..2....1..3....3..2....0..1....2..3....2..4
..1..3....3..5....4..3....2..4....2..0....3..2....5..3....2..0....4..5....1..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 18 2013
STATUS
approved