OFFSET
1,1
COMMENTS
Row 2 of A231263.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) -2*a(n-2) -8*a(n-3) +11*a(n-4) -4*a(n-6) -4*a(n-7) -4*a(n-8) +8*a(n-9).
Empirical g.f.: x*(6 - 9*x - 16*x^2 + 33*x^3 - 3*x^4 - 30*x^5 + x^6 - 2*x^7 + 40*x^8) / ((1 - x)*(1 + x)*(1 - 2*x + 2*x^2)*(1 - 2*x^2)*(1 - 2*x - x^2 - 2*x^3)). - Colin Barker, Feb 16 2018
EXAMPLE
Some solutions for n=3:
..0..0..0..0....0..0..0..1....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..1..1....0..0..1..1....1..1..2..2....0..0..0..0....1..1..1..0
..1..1..1..1....0..1..1..1....1..2..2..2....1..1..1..1....1..1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 06 2013
STATUS
approved