OFFSET
1,1
COMMENTS
Column 8 of A190033.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-1) -a(n-2) +a(n-3) -2*a(n-4) +a(n-5) +a(n-6) -a(n-7) for n>16.
Empirical g.f.: x*(1508 - 2593*x + 1272*x^2 - 1339*x^3 + 2689*x^4 - 1308*x^5 - 1565*x^6 + 1117*x^7 + 9*x^8 + 4*x^9 - 104*x^10 + 16*x^11 - 68*x^12 - 76*x^13 + 361*x^15) / ((1 - x)*(1 - x - x^3 + x^4 - x^6)). - Colin Barker, May 03 2018
EXAMPLE
Some solutions for 4 X 10:
..0..0..1..0..0..0..0..0..1..1....1..0..0..0..0..0..0..0..1..0
..0..0..0..1..0..0..0..0..0..1....0..1..0..0..0..0..0..0..0..0
..0..0..0..0..1..0..0..0..0..0....0..0..1..0..0..0..0..0..0..0
..0..0..0..0..0..1..0..0..0..0....1..0..0..1..0..0..0..0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 04 2011
STATUS
approved