OFFSET
1,1
COMMENTS
Row 3 of A223838.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/720)*n^6 + (1/240)*n^5 + (29/144)*n^4 + (11/48)*n^3 + (1007/360)*n^2 - (37/30)*n + 2.
Conjectures from Colin Barker, Aug 23 2018: (Start)
G.f.: x*(2 - 2*x + x^2)*(2 - 4*x + 5*x^2 - 4*x^3 + 2*x^4) / (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=3:
..1..1..0....0..0..0....0..1..0....1..0..0....1..0..0....0..1..0....0..1..1
..1..1..0....0..1..0....0..1..0....1..1..1....1..1..0....0..1..1....0..1..1
..1..1..1....0..1..0....1..1..0....1..1..1....1..1..0....1..1..1....0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 27 2013
STATUS
approved