OFFSET
1,1
COMMENTS
Column 3 of A201981.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (89/36)*n^6 + (19/12)*n^5 + (215/36)*n^4 - (541/4)*n^3 + (3524/9)*n^2 - (1363/3)*n + 192.
Conjectures from Colin Barker, May 25 2018: (Start)
G.f.: 4*x*(1 + 11*x + 238*x^2 + 257*x^3 - 69*x^4 - 41*x^5 + 48*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=5.
..0..1..3....1..2..3....0..2..3....1..1..3....0..2..3....0..3..3....1..1..3
..2..0..3....2..2..2....1..3..2....1..1..3....1..2..1....2..0..3....1..3..2
..2..3..2....3..2..1....2..1..2....1..2..0....2..1..0....2..0..3....2..1..2
..3..1..1....3..2..1....2..2..0....2..1..0....3..0..0....3..1..2....3..3..0
..3..2..0....3..2..1....2..2..0....3..0..0....3..0..0....3..3..0....3..3..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 07 2011
STATUS
approved