OFFSET
1,1
COMMENTS
Row 4 of A200871.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/360)*n^6 + (7/24)*n^5 + (197/72)*n^4 + (185/24)*n^3 + (1667/180)*n^2 + 5*n + 1.
Conjectures from Colin Barker, Oct 16 2017: (Start)
G.f.: x*(26 - 19*x + 7*x^2 - 28*x^3 + 22*x^4 - 7*x^5 + 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=3
..2....0....2....0....2....1....2....0....3....0....0....1....3....3....1....1
..0....2....2....3....0....2....1....1....3....2....0....1....3....0....2....3
..0....2....2....3....0....2....1....3....0....3....1....1....2....0....2....3
..0....0....2....2....0....2....2....3....0....3....2....0....2....1....2....2
..0....0....1....2....1....1....2....0....2....3....2....0....3....1....2....2
..0....3....1....3....1....0....1....0....2....1....0....0....3....3....2....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 23 2011
STATUS
approved