OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + 5*a(n-4) - 4*a(n-5) + a(n-6).
Empirical for n mod 2 = 0: a(n) = (15/2)*n^4 + 10*n^2 + 11*n + 1.
Empirical for n mod 2 = 1: a(n) = (15/2)*n^4 + 10*n^2 + 11*n - (13/2).
Empirical g.f.: x*(22 + 95*x + 102*x^2 + 144*x^3 - 4*x^4 + x^5) / ((1 - x)^5*(1 + x)). - Colin Barker, Nov 08 2018
EXAMPLE
Some solutions for n=6:
..5....6....0....2....3....3....0....2....2....4....0....6....2....2....3....4
..3....5....2....1....5....3....0....0....5....1....0....4....2....4....6....3
..0....4....3....0....2....3....4....4....6....5....4....6....5....4....4....4
..2....3....3....2....3....2....5....0....0....2....1....4....5....6....2....2
..3....3....5....1....5....2....5....6....4....0....3....2....1....0....5....1
..2....6....2....3....6....2....1....6....1....6....4....2....6....2....1....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 07 2014
STATUS
approved