A223921 Number of 4Xn 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing

15, 225, 2111, 14123, 74040, 323394, 1226491, 4157102, 12856218, 36834899, 98904313, 251078009, 606789828, 1403779390, 3122765753, 6704628063, 13936852281, 28123662137, 55220811463, 105715542647, 197678421680

Offset

1,1

Comments

Row 4 of A223918

Links

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

Formula

Empirical: a(n) = (1/106748928000)*n^16 + (1/2668723200)*n^15 + (29/2335132800)*n^14 + (10013/37362124800)*n^13 + (133979/28740096000)*n^12 + (37333/574801920)*n^11 + (49631/65318400)*n^10 + (1761593/261273600)*n^9 + (219704797/5225472000)*n^8 + (49791911/261273600)*n^7 + (925916249/1437004800)*n^6 + (287406331/179625600)*n^5 + (44691980741/15567552000)*n^4 + (315864449/86486400)*n^3 + (14884357/4324320)*n^2 + (558703/360360)*n + 1

Example

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

Crossrefs

Sequence in context: A221966 A208080 A224264 * A224191 A224349 A224008

Adjacent sequences: A223918 A223919 A223920 * A223922 A223923 A223924

Keyword

nonn

Author

R. H. Hardin Mar 29 2013

Status

approved