OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/90720)*n^9 - (1/6720)*n^8 + (73/15120)*n^7 - (9/160)*n^6 + (2869/4320)*n^5 - (4367/960)*n^4 + (66841/2835)*n^3 - (41101/560)*n^2 + (17105/126)*n - 108 for n>3.
Conjectures from Colin Barker, Sep 09 2018: (Start)
G.f.: x*(3 - 19*x + 64*x^2 - 128*x^3 + 172*x^4 - 167*x^5 + 151*x^6 - 154*x^7 + 151*x^8 - 107*x^9 + 49*x^10 - 13*x^11 + 2*x^12) / (1 - x)^10.
a(n) = 10*a(n-1) - 45*a(n-2) + 120*a(n-3) - 210*a(n-4) + 252*a(n-5) - 210*a(n-6) + 120*a(n-7) - 45*a(n-8) + 10*a(n-9) - a(n-10) for n>13.
(End)
EXAMPLE
Some solutions for n=4:
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..1....0..0..1
..0..0..1....0..0..0....0..1..1....0..1..0....0..1..0....0..0..0....0..0..0
..0..1..0....1..0..0....1..0..0....0..0..1....0..0..0....0..0..1....1..0..1
..0..1..0....0..0..1....0..1..0....1..0..1....0..1..0....0..0..0....0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 18 2013
STATUS
approved