A224045 Number of nX3 0..3 arrays with rows and columns unimodal and antidiagonals nondecreasing

50, 984, 9731, 67585, 376734, 1801402, 7655477, 29502561, 104437965, 342818189, 1051490221, 3033475639, 8279003183, 21484969347, 53256520053, 126598758740, 289630093258, 639706047860, 1367894672765, 2838837855851, 5730717831654

Offset

1,1

Comments

Column 3 of A224050

Links

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

Formula

Empirical: a(n) = (1/3629463552000)*n^18 + (7/403273728000)*n^17 + (667/951035904000)*n^16 + (3253/174356582400)*n^15 + (1895917/5230697472000)*n^14 + (1319281/249080832000)*n^13 + (509321/8211456000)*n^12 + (100859/174182400)*n^11 + (332201027/73156608000)*n^10 + (728354747/24385536000)*n^9 + (143150448337/804722688000)*n^8 + (121759327/136857600)*n^7 + (2559704983/808704000)*n^6 + (221471493559/31135104000)*n^5 + (346834471679/24216192000)*n^4 + (1741800289/181621440)*n^3 + (25437920323/1715313600)*n^2 + (1383692/69615)*n - 32 for n>1

Example

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

Crossrefs

Sequence in context: A006360 A324217 A224059 * A224276 A224199 A112890

Adjacent sequences: A224042 A224043 A224044 * A224046 A224047 A224048

Keyword

nonn

Author

R. H. Hardin Apr 01 2013

Status

approved