OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*a(n-5) - 8*a(n-10).
Empirical g.f.: 4*x*(50 + 66*x + 85*x^2 + 107*x^3 + 132*x^4 - 140*x^5 - 180*x^6 - 226*x^7 - 278*x^8 - 336*x^9) / ((1 - 2*x^5)*(1 - 4*x^5)). - Colin Barker, Nov 07 2018
EXAMPLE
Some solutions for n=6:
..3....2....1....0....0....0....3....3....1....3....1....3....2....1....2....1
..2....3....0....0....0....2....3....2....1....0....1....3....1....2....1....3
..2....3....3....0....2....0....2....1....1....1....3....3....3....0....0....3
..0....0....3....2....0....1....0....1....2....0....1....1....1....2....2....2
..2....3....3....3....3....0....3....1....3....0....0....2....1....2....2....3
..1....1....2....0....0....0....3....3....1....3....1....3....0....1....2....1
..2....3....0....0....0....2....3....2....1....0....1....3....1....2....1....3
..2....3....3....0....2....0....2....1....1....1....3....3....3....0....0....3
..0....0....3....2....0....3....0....1....0....0....1....1....1....2....2....2
..2....3....3....1....3....0....3....1....3....0....0....2....1....2....2....3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 16 2014
STATUS
approved