OFFSET
1,1
COMMENTS
Column 3 of A190098.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-1) -2*a(n-3) +a(n-4) for n>11.
Conjectures from Colin Barker, May 04 2018: (Start)
G.f.: x*(3 + 4*x + 2*x^2 - 2*x^3 - 5*x^4 + 2*x^8 - 2*x^10) / ((1 - x)^3*(1 + x)).
a(n) = (n^2 + 24*n - 56) / 2 for n>7 and even.
a(n) = (n^2 + 24*n - 57) / 2 for n>7 and odd.
(End)
EXAMPLE
Some solutions for n=4:
..0..0....0..2....3..1....1..2....0..0....1..1....3..0....1..0....1..3....0..1
..1..2....2..1....3..2....2..1....0..1....2..3....3..1....1..2....2..1....1..3
..3..3....4..2....4..2....3..2....1..1....4..2....4..1....3..2....4..0....3..2
..2..1....2..3....4..1....2..3....1..0....3..0....4..0....3..0....3..2....2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 04 2011
STATUS
approved