OFFSET
1,1
COMMENTS
Column 2 of A183413.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = a(n-1) + 3*a(n-2) - 3*a(n-3) - 3*a(n-4) + 3*a(n-5) + a(n-6) - a(n-7).
Conjecture: a(n) = (2*n^3+11*n^2+31*n+27+(n^2+n+5)*(-1)^n)/32. - Luce ETIENNE, Nov 18 2014
Empirical g.f.: x*(2 + 3*x - 3*x^2 - 2*x^3 + 3*x^4 + x^5 - x^6) / ((1 - x)^4*(1 + x)^3). - Colin Barker, Mar 29 2018
EXAMPLE
Some solutions for 4 X 2:
..0..0....0..0....0..0....0..0....0..0....0..1....0..1....0..0....0..0....0..1
..0..0....0..1....0..0....0..1....0..0....0..1....0..1....0..1....0..0....0..1
..0..0....1..0....0..0....0..1....0..1....0..1....1..0....1..0....0..1....0..1
..1..1....1..1....0..1....0..1....1..0....1..0....1..0....1..0....0..1....0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 04 2011
STATUS
approved