OFFSET
1,1
COMMENTS
Column 6 of A252820.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = (1/11404800)*n^12 + (1/211200)*n^11 + (37/345600)*n^10 + (143/103680)*n^9 + (27977/2419200)*n^8 + (83399/1209600)*n^7 + (319693/1036800)*n^6 + (34283/34560)*n^5 + (59941/28800)*n^4 + (482543/129600)*n^3 + (720359/277200)*n^2 + (44551/13860)*n + 3.
EXAMPLE
Some solutions for n=4
..0..1..2..3..4..5....0..1..2..3..4..5....0..1..2..3..3..4....0..1..2..2..3..4
..1..2..2..3..4..5....1..2..3..4..4..5....1..2..3..4..4..5....1..2..2..2..3..4
..2..3..3..3..4..5....2..2..3..4..5..5....1..2..3..4..5..5....2..3..3..3..4..5
..3..3..3..4..5..6....3..3..4..5..5..6....1..2..3..4..5..6....3..4..4..4..5..6
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 22 2014
STATUS
approved