A252826 Number of nX6 nonnegative integer arrays with upper left 0 and every value within 3 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down

26, 339, 3891, 36292, 271846, 1679072, 8807722, 40232545, 163307844, 598768118, 2009666884, 6242686351, 18111918515, 49456857086, 127928520595, 315195592486, 743219906659, 1684034391078, 3679765581966, 7778027858175, 15947032415637

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

Sequence in context: A125438 A126919 A035708 * A042306 A329300 A053494

Adjacent sequences: A252823 A252824 A252825 * A252827 A252828 A252829

Keyword

nonn

Author

R. H. Hardin, Dec 22 2014

Status

approved