OFFSET
1,1
COMMENTS
Column 3 of A203181.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-2) +10*a(n-3) +5*a(n-4) -a(n-5) -31*a(n-6) -7*a(n-7) +30*a(n-9) for n>10.
Empirical G.f.:
2*x -x^2*(2+7*x+13*x^2+7*x^3-17*x^4-50*x^5-13*x^6+18*x^7+54*x^8) / ( -1+2*x^2+10*x^3+5*x^4-x^5-31*x^6-7*x^7+30*x^9 ). - R. J. Mathar, Jul 02 2013
EXAMPLE
Some solutions for n=5:
..0..1..2....0..1..2....0..1..0....0..1..2....0..1..2....0..1..2....0..1..0
..1..0..1....1..0..1....1..0..1....1..0..1....1..0..1....1..0..1....1..0..1
..2..1..0....0..1..2....0..1..0....2..1..0....0..1..0....0..1..2....2..1..2
..0..1..1....1..0..1....1..0..1....0..2..1....1..2..1....1..0..1....0..1..0
..1..0..2....0..1..0....0..1..0....1..0..2....2..0..1....0..1..2....1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 30 2011
STATUS
approved