A224059 Number of nX3 0..3 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing

50, 984, 8854, 58814, 324702, 1557606, 6643979, 25596389, 90177585, 293585050, 891208427, 2542007013, 6857916671, 17598839738, 43168340844, 101638636169, 230538577645, 505352928460, 1073534755140, 2215475595868, 4451276849868

Offset

1,1

Comments

Column 3 of A224064

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = (1/3629463552000)*n^18 + (1/80654745600)*n^17 + (673/1307674368000)*n^16 + (3163/237758976000)*n^15 + (208801/747242496000)*n^14 + (625841/149448499200)*n^13 + (1696897/28740096000)*n^12 + (14064731/28740096000)*n^11 + (339240647/73156608000)*n^10 + (339530671/14631321600)*n^9 + (4767368563/28740096000)*n^8 + (637757023/1026432000)*n^7 + (26329719541/10378368000)*n^6 + (2426824577/339655680)*n^5 + (343572662101/18162144000)*n^4 - (189957341011/9081072000)*n^3 + (1627071089/5834400)*n^2 - (2276993179/3063060)*n + 701 for n>3

Example

Some solutions for n=3
..3..0..0....0..0..0....0..0..2....2..2..1....1..1..0....1..1..1....2..0..0
..3..3..1....1..1..0....1..1..2....1..2..3....1..1..1....0..1..3....1..3..2
..0..3..3....1..2..3....1..1..3....0..2..3....0..1..2....0..1..3....1..1..3

Crossrefs

Sequence in context: A101929 A006360 A324217 * A224045 A224276 A224199

Adjacent sequences: A224056 A224057 A224058 * A224060 A224061 A224062

Keyword

nonn

Author

R. H. Hardin Mar 30 2013

Status

approved