OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 3*a(n-2) - 8*a(n-3) - 2*a(n-4) + 12*a(n-5) - 2*a(n-6) - 8*a(n-7) + 3*a(n-8) + 2*a(n-9) - a(n-10).
Conjectures from Colin Barker, Nov 05 2018: (Start)
G.f.: x*(110 + 2747*x + 5836*x^2 + 8680*x^3 + 3456*x^4 - 2178*x^5 - 1148*x^6 - 224*x^7 + 2*x^8 - x^9) / ((1 - x)^6*(1 + x)^4).
a(n) = 1 + 37*n + 43*n^2 + 126*n^3 + 89*n^4 + 9*n^5 for n even.
a(n) = 7 - 76*n - 41*n^2 + 122*n^3 + 89*n^4 + 9*n^5 for n odd.
(End)
EXAMPLE
Some solutions for n=5:
..2....4....0....4....0....0....2....3....4....2....3....3....4....1....1....5
..2....1....5....3....2....3....4....0....1....0....3....5....3....3....0....0
..3....2....1....2....3....2....1....5....5....5....2....0....2....2....4....5
..2....3....4....3....0....5....3....0....0....3....3....1....5....5....5....2
..3....3....1....2....5....3....4....0....4....2....0....4....3....3....0....3
..3....2....2....4....3....2....1....5....1....0....5....2....2....2....5....5
..2....2....3....1....2....2....4....3....4....3....2....1....2....3....4....2
..3....3....2....0....1....3....2....2....2....2....0....3....3....2....1....0
..1....2....4....4....3....2....1....0....3....4....3....2....5....4....5....5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 04 2014
STATUS
approved