OFFSET
1,1
COMMENTS
Row 4 of A224409.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/40320)*n^8 + (1/1440)*n^7 + (31/2880)*n^6 + (13/144)*n^5 + (3767/5760)*n^4 + (6409/1440)*n^3 + (189859/10080)*n^2 - (73/24)*n - 7 for n>2.
Conjectures from Colin Barker, Aug 30 2018: (Start)
G.f.: x*(16 - 36*x - 38*x^2 + 206*x^3 - 196*x^4 - 106*x^5 + 368*x^6 - 334*x^7 + 155*x^8 - 38*x^9 + 4*x^10) / (1 - x)^9.
a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>11.
(End)
EXAMPLE
Some solutions for n=3:
..0..0..0....0..0..0....0..0..0....1..0..0....0..0..0....1..1..0....0..0..0
..0..0..1....0..0..0....1..1..0....0..1..1....1..1..0....1..1..0....1..0..0
..0..1..0....1..1..1....1..1..1....1..1..1....1..0..0....1..1..0....0..1..0
..1..0..0....1..1..1....1..1..1....1..1..0....0..1..0....1..0..0....1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 05 2013
STATUS
approved