A223985 Number of nX6 0..3 arrays with rows unimodal and columns nondecreasing.
610, 52591, 1738756, 31585056, 378122264, 3322756326, 22985966340, 131366850521, 642224541548, 2756467192963, 10596041132366, 37055725164722, 119377525079194, 357900074208050, 1006959166065982, 2677364150668003
Offset: 1
Keywords
Examples
Some solutions for n=3 ..0..0..2..2..0..0....0..0..1..2..0..0....0..0..1..1..3..0....0..0..3..3..3..1 ..0..0..2..2..1..0....0..0..1..2..3..0....0..0..1..3..3..1....0..2..3..3..3..2 ..0..0..3..3..1..0....0..2..2..2..3..3....0..2..2..3..3..2....0..2..3..3..3..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = (42587101/1600593426432000)*n^18 + (23341517/16167610368000)*n^17 + (1146376367/31384184832000)*n^16 + (6480623/11321856000)*n^15 + (97670169131/15692092416000)*n^14 + (12419845481/249080832000)*n^13 + (1104278423317/3621252096000)*n^12 + (292799530697/201180672000)*n^11 + (1205682607421/219469824000)*n^10 + (57526246621/3483648000)*n^9 + (95561855720567/2414168064000)*n^8 + (16411079047/217728000)*n^7 + (1328902382698939/11769069312000)*n^6 + (7779741596449/59439744000)*n^5 + (74800773679601/653837184000)*n^4 + (94051748107/1297296000)*n^3 + (483108777911/15437822400)*n^2 + (50380667/6126120)*n + 1
Comments