OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/35)*n^7 + (8/5)*n^6 + (56/5)*n^5 + 25*n^4 + (249/10)*n^3 + (77/5)*n^2 + (481/70)*n + 1.
Conjectures from Colin Barker, Dec 17 2018: (Start)
G.f.: x*(86 + 452*x + 96*x^2 - 601*x^3 + 122*x^4 - 18*x^5 + 8*x^6 - x^7) / (1 - x)^8.
a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.
(End)
EXAMPLE
Some solutions for n=5:
..3....1....3....0....2....1....0....4....4....4....4....3....4....2....0....3
..3....0....2....4....3....5....5....1....0....5....1....1....0....2....4....3
..3....0....2....2....0....4....1....0....0....3....2....1....4....1....3....5
..5....0....3....2....5....3....5....1....0....3....1....0....0....0....0....3
..3....5....2....3....2....3....1....1....5....3....1....3....0....1....0....3
..3....3....2....1....2....1....0....1....0....3....3....1....0....3....0....3
..1....0....2....2....3....3....1....4....0....0....0....1....2....1....0....4
..5....0....4....4....0....4....2....2....1....5....2....3....1....2....0....2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 05 2015
STATUS
approved