OFFSET
1,1
COMMENTS
Column 6 of A252828
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 + (813736283/7242504192000)*n^12 + (166116079/201180672000)*n^11 + (1097726573/219469824000)*n^10 + (598115773/24385536000)*n^9 + (466445792503/4828336128000)*n^8 + (272090281/870912000)*n^7 + (19554578278049/23538138624000)*n^6 + (1173600978721/653837184000)*n^5 + (4602055984369/1307674368000)*n^4 + (98334957191/18162144000)*n^3 + (263932729939/30875644800)*n^2 + (3637273/816816)*n + 1
EXAMPLE
Some solutions for n=4
..0..1..2..3..3..3....0..1..2..3..3..3....0..0..1..2..2..2....0..1..1..1..1..2
..1..2..3..3..4..4....1..1..2..3..3..3....1..1..2..2..2..3....0..1..2..2..2..3
..1..2..3..4..4..4....1..2..3..3..4..4....1..1..2..3..3..4....1..2..2..3..3..4
..2..3..4..5..5..5....2..3..3..4..5..5....1..2..3..4..4..5....2..2..3..4..4..5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 22 2014
STATUS
approved