OFFSET
1,1
COMMENTS
Column 8 of A189326.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = (1/3)*n^3 + 10*n^2 + (587/3)*n - 1558 for n>10.
Empirical g.f.: x*(13 - 28*x + 31*x^2 - 9*x^3 + 10*x^4 + 3*x^5 + 7*x^6 - 21*x^7 - 14*x^8 - 10*x^9 + 2*x^10 + 10*x^11 + 7*x^12 + x^13) / (1 - x)^4. - Colin Barker, May 02 2018
EXAMPLE
Some solutions for n=3:
..2....0....1....1....2....7....2....4....3....1....0....4....1....3....3....2
..4....4....6....3....6....8....3....4....5....4....4....4....7....5....4....4
..6....4....7....4....8....8....3....4....5....4....4....4....7....5....4....4
..8....4....7....4....8....8....5....8....8....5....8....4....8....5....4....6
..8....8....8....8....8....8....8....8....8....8....8....8....8....8....8....8
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 20 2011
STATUS
approved