A224191 Number of 4Xn 0..2 arrays with rows unimodal and columns nondecreasing

15, 225, 2205, 15779, 89380, 422488, 1727738, 6272940, 20614382, 62231446, 174603882, 459586532, 1143581612, 2707062766, 6128575771, 13328965295, 27955737041, 56730240471, 111704250407, 213954477597, 399506181220

Offset

1,1

Comments

Row 4 of A224190

Links

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

Formula

Empirical: a(n) = (1/106748928000)*n^16 + (1/1482624000)*n^15 + (7/266872320)*n^14 + (127/197683200)*n^13 + (311999/28740096000)*n^12 + (212351/1596672000)*n^11 + (31937/26127360)*n^10 + (83129/9676800)*n^9 + (34840531/746496000)*n^8 + (9481183/48384000)*n^7 + (90994151/143700480)*n^6 + (123257231/79833600)*n^5 + (43399375531/15567552000)*n^4 + (2360326763/648648000)*n^3 + (218135/61776)*n^2 + (581099/360360)*n + 1

Example

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

Crossrefs

Sequence in context: A208080 A224264 A223921 * A224349 A224008 A012852

Adjacent sequences: A224188 A224189 A224190 * A224192 A224193 A224194

Keyword

nonn

Author

R. H. Hardin Apr 01 2013

Status

approved