OFFSET
1,2
COMMENTS
Column 7 of A221524.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) +21*a(n-2) +58*a(n-3) +79*a(n-4) +32*a(n-5) +23*a(n-6) +4*a(n-7) +8*a(n-8).
Empirical g.f.: 2*x^2*(21 + 48*x + 108*x^2 + 34*x^3 + 36*x^4 + 12*x^6) / (1 - 3*x - 21*x^2 - 58*x^3 - 79*x^4 - 32*x^5 - 23*x^6 - 4*x^7 - 8*x^8). Colin Barker, Oct 18 2017
EXAMPLE
Some solutions for n=6
..5....1....3....1....0....6....4....5....2....7....5....7....1....0....0....0
..3....4....7....6....3....3....6....2....5....3....0....5....6....4....3....4
..5....0....3....5....5....0....4....0....4....3....1....4....5....4....5....4
..6....0....1....1....0....4....7....2....2....5....6....7....3....7....7....2
..1....4....0....5....3....6....1....0....6....2....6....0....2....1....6....5
..4....6....2....7....0....0....3....6....2....5....0....7....6....5....3....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 19 2013
STATUS
approved