OFFSET
1,1
COMMENTS
Column 5 of A183904.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..57
FORMULA
Empirical: a(n) = (1/120)*n^5 + (1/4)*n^4 + (71/24)*n^3 + (57/4)*n^2 - (262/15)*n - 50 for n>4.
Conjectures from Colin Barker, Apr 05 2018: (Start)
G.f.: x*(3 + 6*x + 31*x^2 - 116*x^3 + 102*x^4 - 38*x^5 + 59*x^6 - 78*x^7 + 38*x^8 - 6*x^9) / (1 - x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>10.
(End)
EXAMPLE
Some solutions for n=2:
..0....1....0....0....0....0....0....0....0....0....0....3....1....3....0....1
..2....3....0....1....0....0....0....1....2....1....0....3....3....3....2....1
..4....5....2....3....2....2....0....1....4....2....4....5....3....3....2....1
..4....5....4....4....2....2....0....2....5....3....4....5....5....3....2....3
..4....5....4....5....4....2....0....4....5....4....4....5....5....3....4....3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 07 2011
STATUS
approved