OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - 4*a(n-5) + 6*a(n-6) - 4*a(n-7) + a(n-8) for n>14.
Empirical g.f.: x*(988 - 3269*x + 5113*x^2 - 4208*x^3 + 2176*x^4 + 374*x^5 - 2954*x^6 + 2530*x^7 - 1622*x^8 + 1571*x^9 - 743*x^10 + 82*x^11 + 6*x^12 + 4*x^13) / ((1 - x)^5*(1 + x)*(1 + x^2)). - Colin Barker, Dec 22 2018
EXAMPLE
Some solutions for n=4:
..0..0..0..0..0..0..1....0..0..0..0..0..0..1....1..0..0..0..0..0..1
..0..0..0..0..0..1..1....1..0..0..0..0..0..0....1..0..0..0..0..0..0
..1..1..0..0..1..1..1....1..0..0..0..0..0..0....0..0..0..0..0..0..1
..1..0..0..1..1..1..1....1..0..0..0..0..0..1....1..1..1..1..1..1..1
..1..0..1..1..1..1..1....0..0..0..0..0..0..1....1..1..1..1..0..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 03 2015
STATUS
approved