OFFSET
1,1
COMMENTS
Row 3 of A211561.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/8)*n^4 + (5/12)*n^3 + (7/8)*n^2 + (19/12)*n + 2.
Empirical: a(n) = sum{j in n..n+2}stirling2(n+2,j).
Conjectures from Colin Barker, Jul 19 2018: (Start)
G.f.: x*(5 - 11*x + 16*x^2 - 9*x^3 + 2*x^4) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.
(End)
EXAMPLE
Some solutions for n=5:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....1
..2....2....2....2....2....2....0....0....2....2....2....1....2....2....2....2
..3....1....2....3....3....0....2....2....2....0....3....2....3....3....3....3
..0....1....1....3....2....3....2....0....3....1....4....3....4....4....1....4
..4....3....3....1....0....2....3....3....4....3....3....2....5....3....2....0
..4....4....4....4....4....4....4....4....1....4....1....4....4....5....4....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 15 2012
STATUS
approved