OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 5*a(n-1) + 2*a(n-2) + 5*a(n-3) + a(n-4).
Empirical g.f.: 8*x*(235 + 122*x + 222*x^2 + 43*x^3) / (1 - 5*x - 2*x^2 - 5*x^3 - x^4). - Colin Barker, Nov 06 2018
EXAMPLE
Some solutions for n=3:
..5....0....1....0....2....4....6....0....2....5....6....7....2....7....7....7
..7....5....0....1....6....0....5....4....1....3....2....3....0....3....6....4
..5....6....1....4....7....1....6....1....7....1....6....6....3....3....4....7
..5....6....5....2....6....0....7....0....1....7....7....5....6....1....5....4
..5....0....0....2....2....2....6....0....5....7....6....5....5....2....4....7
..1....6....1....6....3....4....2....3....1....5....2....5....3....7....4....5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 27 2014
STATUS
approved