OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*a(n-1) - 14*a(n-2) + 14*a(n-3) - 14*a(n-5) + 14*a(n-6) - 6*a(n-7) + a(n-8).
Empirical for n mod 2 = 0: a(n) = n^6 + 6*n^5 + (15/2)*n^4 + 20*n^3 + 5*n^2 - 5*n.
Empirical for n mod 2 = 1: a(n) = n^6 + 6*n^5 + (15/2)*n^4 + 20*n^3 + 5*n^2 - 5*n + (15/2).
Empirical g.f.: 6*x*(7 + 49*x + 114*x^2 + 54*x^3 + 39*x^4 - 23*x^5) / ((1 - x)^7*(1 + x)). - Colin Barker, Nov 08 2018
EXAMPLE
Some solutions for n=6:
..2....3....1....3....4....3....1....1....4....0....2....1....0....0....1....0
..5....1....3....4....2....3....5....1....0....2....2....2....6....0....0....3
..4....0....5....2....2....1....3....3....3....3....0....5....5....1....5....3
..4....2....3....3....3....5....2....2....2....2....4....5....3....3....4....0
..0....2....2....4....2....2....6....0....4....3....3....4....2....1....3....3
..4....0....2....3....2....3....5....5....3....1....6....0....6....6....1....2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 06 2014
STATUS
approved