OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = n^6 + 9*n^5 + 20*n^4 + (68/3)*n^3 + 12*n^2 + (7/3)*n + 1.
Conjectures from Colin Barker, Nov 12 2018: (Start)
G.f.: x*(68 + 431*x + 343*x^2 - 96*x^3 - 20*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=6:
..2....0....3....0....4....4....3....3....0....2....2....2....3....0....0....3
..1....0....4....6....5....0....5....5....2....2....2....2....4....5....0....5
..3....2....5....2....5....2....6....2....2....0....1....4....3....5....6....3
..3....2....6....3....5....2....6....0....3....1....2....3....4....2....0....5
..4....5....4....2....3....2....3....2....4....5....5....3....6....2....0....5
..3....6....1....0....5....4....5....2....2....2....1....3....6....0....0....5
..5....1....4....2....0....4....0....0....1....5....5....6....1....2....4....4
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 19 2014
STATUS
approved