OFFSET
1,1
COMMENTS
Row 5 of A221463.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..137
FORMULA
Empirical: a(n) = 1*n^4 + 2*n^3.
Conjectures from Colin Barker, Aug 05 2018: (Start)
G.f.: x*(3 + 17*x + 5*x^2 - x^3) / (1 - x)^5.
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>5.
(End)
EXAMPLE
Some solutions for n=6:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..5....6....3....4....4....1....1....4....5....3....4....4....5....6....5....6
..0....6....1....5....5....5....3....5....1....3....0....4....5....4....3....0
..2....5....2....5....5....3....0....3....0....4....0....3....2....0....2....2
..5....0....1....4....2....0....4....5....6....3....1....2....0....6....0....4
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 17 2013
STATUS
approved