OFFSET
1,1
COMMENTS
Column 3 of A223644.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (23/360)*n^6 - (3/40)*n^5 + (31/18)*n^4 + (5/8)*n^3 + (1517/360)*n^2 - (51/20)*n + 3.
Conjectures from Colin Barker, Aug 22 2018: (Start)
G.f.: x*(7 + 22*x^2 - 16*x^3 + 40*x^4 - 10*x^5 + 3*x^6) / (1 - x)^7.
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.
(End)
EXAMPLE
Some solutions for n=4:
..0..1..1....1..1..0....0..0..0....0..1..0....0..1..1....0..1..0....0..0..1
..0..1..1....1..1..0....1..1..0....1..1..0....1..1..0....1..1..0....0..0..1
..1..1..0....1..1..0....1..1..0....0..1..1....0..0..0....1..1..0....0..1..1
..1..0..0....0..0..1....0..0..1....0..0..1....0..0..0....1..0..0....0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 24 2013
STATUS
approved