OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = n^5 + 5*n^4 + 10*n^3 + 5*n^2 + 17*n + 2 for n>2.
Conjectures from Colin Barker, Nov 13 2018: (Start)
G.f.: x*(32 + 51*x + 38*x^2 + 3*x^3 + 8*x^4 - 29*x^5 + 22*x^6 - 5*x^7) / (1 - x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>8.
(End)
EXAMPLE
Some solutions for n=6:
..1....2....1....2....5....3....5....4....4....3....3....6....2....2....1....3
..3....2....7....4....6....5....5....3....1....1....5....2....7....5....1....7
..6....2....6....5....8....2....4....3....5....7....6....5....8....6....3....4
..4....3....4....8....8....5....6....9....7....4....6....8....4....5....9....9
..4....7....9....4...10...10...10....9....4...10....4...10....9....4...10...10
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 19 2014
STATUS
approved