OFFSET
1,1
COMMENTS
Column 2 of A247726
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) +2*a(n-4) -4*a(n-5).
Empirical G.f.: -2*x*(-24+3*x+4*x^2+5*x^3+54*x^4) / ( (2*x-1)*(2*x^4-1) ). - R. J. Mathar, Sep 23 2014
EXAMPLE
Some solutions for n=6
..1....2....2....2....2....2....1....0....2....2....1....0....1....0....1....2
..0....1....0....0....0....0....0....0....0....2....2....2....2....2....0....2
..0....0....1....2....2....0....0....2....1....2....0....2....0....2....2....1
..0....0....2....1....1....1....2....0....2....0....0....1....2....1....0....2
..1....0....0....0....2....0....1....1....0....2....1....2....2....2....0....2
..0....1....0....2....2....2....2....0....0....2....2....2....2....0....0....0
..0....2....0....0....2....2....0....2....1....1....0....0....1....0....1....1
..2....0....1....1....0....1....2....0....0....0....2....1....2....1....0....2
..1....2....0....0....1....2....2....0....0....2....2....2....2....2....2....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 23 2014
STATUS
approved