OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
Robert Israel, Maple-assisted proof of empirical recurrence
FORMULA
Empirical: a(n) = 7*a(n-1) - 7*a(n-2) - 34*a(n-3) + 59*a(n-4) + 27*a(n-5) - 87*a(n-6) + 36*a(n-7).
Empirical g.f.: x*(38 - 114*x - 233*x^2 + 727*x^3 + 153*x^4 - 1083*x^5 + 504*x^6) / ((1 - x)*(1 - 5*x + 3*x^2)*(1 - 3*x^2)*(1 - x - 4*x^2)). - Colin Barker, Sep 05 2018
Empirical recurrence confirmed (see link). - Robert Israel, Jun 18 2019
EXAMPLE
Some solutions for n=3:
..0..0..1....1..0..0....1..0..1....0..0..1....1..0..0....1..0..1....1..0..1
..0..0..0....0..0..1....0..1..0....1..0..0....1..0..0....1..1..1....1..0..1
..1..1..1....1..0..0....1..0..1....1..0..1....0..0..1....0..1..0....0..0..0
..0..0..0....1..0..0....1..1..1....1..0..1....1..0..1....1..1..1....1..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 17 2013
STATUS
approved