OFFSET
1,2
COMMENTS
Row 6 of A215228.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = n^6 - 6*n^4 + 5*n^3 + 5*n^2 - 5*n.
Conjectures from Colin Barker, Jul 23 2018: (Start)
G.f.: 6*x^2*(3 + 47*x + 77*x^2 - 7*x^3) / (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=5:
..2....1....5....4....3....0....4....5....1....4....2....5....3....1....1....5
..0....3....2....2....1....4....1....4....2....1....3....3....4....4....4....1
..5....4....3....3....2....1....2....2....3....3....1....5....5....1....0....4
..0....5....0....2....4....5....4....0....2....2....3....0....0....5....4....2
..4....1....1....0....0....4....5....4....0....5....4....2....1....2....3....3
..1....2....3....2....5....3....2....3....5....3....5....0....5....0....5....4
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 06 2012
STATUS
approved