OFFSET
1,5
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (4096/3)*n^3 - 22816*n^2 + (388490/3)*n - 249567 for n>6.
Conjectures from Colin Barker, Dec 08 2018: (Start)
G.f.: x*(1 - 3*x + 3*x^2 - x^3 + 68*x^4 + 859*x^5 + 3118*x^6 + 2810*x^7 + 1154*x^8 + 183*x^9) / (1 - x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>10.
(End)
EXAMPLE
Some solutions for n=6:
..0..0..0..0....0..0..0..0....0..0..0..0....0..1..1..1....0..1..1..2
..0..0..0..1....1..1..1..1....0..1..1..1....0..1..1..1....1..1..1..2
..0..1..1..1....1..1..2..2....1..1..1..2....1..1..2..2....1..1..1..2
..0..1..2..2....1..1..2..2....2..2..2..2....1..2..2..2....1..1..1..2
..1..1..2..2....1..2..2..2....2..2..2..2....1..2..2..2....1..1..1..2
..2..2..2..2....2..2..2..2....2..2..2..2....2..2..2..2....2..2..2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 25 2014
STATUS
approved