OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + a(n-3) + 14*a(n-4) + 3*a(n-5) + 6*a(n-6) + a(n-8) + a(n-9).
Empirical g.f.: 4*x*(43 + 35*x + 102*x^2 + 245*x^3 + 80*x^4 + 99*x^5 + 7*x^6 + 21*x^7 + 16*x^8) / (1 - 2*x - x^3 - 14*x^4 - 3*x^5 - 6*x^6 - x^8 - x^9). - Colin Barker, Nov 06 2018
EXAMPLE
Some solutions for n=6:
..4....4....0....0....1....2....3....3....3....3....1....3....0....0....4....1
..4....4....0....3....1....0....4....4....2....3....1....0....0....0....2....2
..3....1....0....3....0....3....2....4....0....4....1....3....0....0....3....1
..4....2....1....3....1....3....4....4....0....4....4....0....2....3....4....1
..4....1....1....0....0....0....3....1....3....3....1....3....1....3....4....4
..4....4....2....2....2....0....4....4....0....4....1....0....0....3....4....4
..4....4....4....3....1....0....4....1....2....4....1....0....1....2....4....2
..3....4....1....3....0....3....4....2....0....2....4....2....1....3....4....3
..2....4....4....0....0....3....4....1....3....4....2....3....1....4....4....3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 27 2014
STATUS
approved