OFFSET
1,1
COMMENTS
Column 4 of A222127.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + a(n-3) + 2*a(n-5) - a(n-6).
Empirical g.f.: x*(2 + x + x^2 + 2*x^3 + x^4 - x^5) / (1 - x - x^3 - 2*x^5 + x^6). - Colin Barker, Aug 15 2018
EXAMPLE
Some solutions for n=7, one extended zero followed by filtered positions:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....0....1....0....1....0....0....0....0....0....0....0....0....0....1....1
..1....1....0....0....0....1....0....1....1....0....1....0....1....0....0....0
..0....0....0....1....1....0....0....0....0....0....0....1....0....0....0....0
..0....1....1....0....0....1....0....0....0....0....0....0....1....1....0....1
..1....0....0....0....0....0....1....0....0....0....1....0....0....0....0....0
..0....0....0....0....0....0....0....1....0....0....0....1....1....1....0....0
..1....1....1....0....1....0....0....0....1....0....0....0....0....0....1....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 08 2013
STATUS
approved