OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) - 2*a(n-3) + a(n-4) for n>8.
Empirical for n mod 2 = 0: a(n) = 4*n^2 + (45/2)*n + 41 for n>4.
Empirical for n mod 2 = 1: a(n) = 4*n^2 + (45/2)*n + (75/2) for n>4.
Empirical g.f.: x*(44 + 14*x - 61*x^2 - x^3 + 16*x^4 + 4*x^5 + 2*x^6 - 2*x^7) / ((1 - x)^3*(1 + x)). - Colin Barker, Dec 11 2018
EXAMPLE
Some solutions for n=4:
..1..1..1....1..1..1....0..1..1....1..1..1....1..1..1....0..1..0....1..0..1
..1..1..1....1..1..0....0..0..0....1..1..0....0..1..0....1..1..0....0..0..0
..1..1..0....1..1..1....0..0..1....0..1..0....0..1..0....1..1..0....0..1..0
..0..1..0....0..0..0....0..0..1....0..1..0....0..1..0....1..1..1....0..1..0
..0..1..0....0..1..1....0..0..1....0..1..0....0..1..0....1..0..0....0..1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 31 2014
STATUS
approved