A223720 Number of n X 3 0..2 arrays with rows, antidiagonals and columns unimodal.

22, 484, 5883, 46613, 273562, 1285547, 5087912, 17557701, 54161878, 152154419, 394849354, 957192985, 2187192034, 4745347460, 9834757897, 19568773673, 37541913638, 69694254022, 125590862829, 220277446621, 376922731034

Offset

1,1

Comments

Column 3 of A223725.

Links

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

Formula

Empirical: a(n) = (5051/239500800)*n^12 + (61/177408)*n^11 + (91271/21772800)*n^10 + (27/896)*n^9 + (1198121/7257600)*n^8 + (1087/1792)*n^7 + (36617153/21772800)*n^6 + (63719/20160)*n^5 + (26821099/5443200)*n^4 + (305/56)*n^3 + (149993/207900)*n^2 + (3277/770)*n + 1.

Example

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

Crossrefs

Cf. A223725.

Sequence in context: A207721 A223737 A223635 * A223667 A223826 A223618

Adjacent sequences: A223717 A223718 A223719 * A223721 A223722 A223723

Keyword

nonn

Author

R. H. Hardin, Mar 26 2013

Status

approved