OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = n^4 + 2*n^3 + 3*n^2 + 2*n.
Conjectures from Colin Barker, Nov 07 2018: (Start)
G.f.: 8*x*(1 + x + x^2) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.
(End)
EXAMPLE
Some solutions for n=6:
..0....4....1....2....0....1....4....0....4....0....3....0....0....0....3....2
..1....4....0....5....6....5....6....3....1....5....6....3....5....2....0....5
..2....2....1....3....5....1....4....6....0....1....6....3....5....0....1....2
..5....3....5....3....3....0....3....5....2....5....2....4....5....0....1....4
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 23 2014
STATUS
approved