A223983 Number of nX4 0..3 arrays with rows unimodal and columns nondecreasing

130, 3526, 44803, 358118, 2086196, 9647292, 37395816, 126087157, 379654704, 1040942916, 2637614941, 6248087300, 13964013792, 29662913488, 60254807616, 117633453657, 221649696158, 404535879938, 717351048575, 1239192239626

Offset

1,1

Comments

Column 4 of A223987

Links

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

Formula

Empirical: a(n) = (3551/47900160)*n^12 + (89357/39916800)*n^11 + (132341/4354560)*n^10 + (177787/725760)*n^9 + (1892753/1451520)*n^8 + (5834147/1209600)*n^7 + (11057083/870912)*n^6 + (17370313/725760)*n^5 + (6973385/217728)*n^4 + (26874943/907200)*n^3 + (186503/10395)*n^2 + (8831/1386)*n + 1

Example

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

Crossrefs

Sequence in context: A168124 A224169 A223860 * A224060 A224046 A224277

Adjacent sequences: A223980 A223981 A223982 * A223984 A223985 A223986

Keyword

nonn

Author

R. H. Hardin Mar 30 2013

Status

approved