OFFSET
1,1
COMMENTS
Column 6 of A252976
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (883/1600593426432000)*n^18 + (883/16167610368000)*n^17 + (148963/62768369664000)*n^16 + (6599/108972864000)*n^15 + (8020459/7846046208000)*n^14 + (3062099/249080832000)*n^13 + (813101243/7242504192000)*n^12 + (165163519/201180672000)*n^11 + (1074230093/219469824000)*n^10 + (564482173/24385536000)*n^9 + (410608176823/4828336128000)*n^8 + (212043001/870912000)*n^7 + (12296690400809/23538138624000)*n^6 + (525004330021/653837184000)*n^5 + (1880413300609/1307674368000)*n^4 + (10237127057/6054048000)*n^3 + (183696263083/30875644800)*n^2 + (15176011/12252240)*n - 2
EXAMPLE
Some solutions for n=4
..0..1..1..2..3..4....0..1..2..2..3..4....0..1..1..2..3..3....0..1..1..2..3..3
..0..1..2..3..4..4....1..2..3..3..3..4....0..1..2..2..3..4....1..1..2..2..3..3
..1..2..3..4..4..4....2..3..3..3..3..4....0..1..2..3..4..5....1..2..2..3..3..4
..2..3..3..4..4..5....3..3..3..4..4..5....1..2..3..4..4..5....2..2..2..3..4..5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 25 2014
STATUS
approved