OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (53/360)*n^6 + (5/4)*n^5 + (307/72)*n^4 + (91/12)*n^3 + (683/90)*n^2 + (25/6)*n + 1.
Conjectures from Colin Barker, Oct 30 2018: (Start)
G.f.: x*(26 + 36*x + 63*x^2 - 34*x^3 + 21*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=4:
..3....1....1....0....1....2....2....1....0....1....2....0....2....1....3....2
..1....3....1....1....2....0....1....0....3....0....1....0....1....3....0....2
..2....1....1....1....2....1....0....2....1....0....2....2....2....2....1....1
..0....2....0....3....1....4....3....1....1....4....0....0....3....1....1....0
..1....1....0....3....0....0....1....0....1....0....3....1....0....1....0....0
..4....1....1....0....0....1....0....2....2....1....0....4....0....1....0....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 02 2014
STATUS
approved