OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/8064)*n^8 + (1/288)*n^7 + (103/2880)*n^6 + (17/90)*n^5 + (655/1152)*n^4 + (331/288)*n^3 - (677/1120)*n^2 - (41/120)*n + 2.
Empirical: G.f.: -x*(3-x+27*x^2-78*x^3+120*x^4-110*x^5+59*x^6-17*x^7+2*x^8) / (x-1)^9. - R. J. Mathar, Nov 23 2015
EXAMPLE
Some solutions for n=3
..0..0..1..1....0..0..0..1....0..0..1..1....0..1..1..2....0..1..1..1
..0..0..1..2....0..0..1..2....0..1..2..2....0..1..2..2....0..1..1..2
..1..1..2..3....0..1..2..3....1..2..3..3....0..1..2..3....1..1..2..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 24 2014
STATUS
approved