A223845 Number of nX3 0..3 arrays with rows and columns unimodal

50, 2500, 64660, 1006318, 10804883, 87613063, 570145144, 3107412546, 14632983606, 60951077586, 228682697934, 784020062496, 2484771896660, 7348846431262, 20442258040721, 53835488429681, 134975315832464

Offset

1,1

Comments

Column 3 of A223850

Links

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

Formula

Empirical: a(n) = (89/169374965760)*n^18 + (811/30536352000)*n^17 + (2373533/3487131648000)*n^16 + (699851/62270208000)*n^15 + (11519407/87178291200)*n^14 + (51637/44352000)*n^13 + (7243453/912384000)*n^12 + (306562541/7185024000)*n^11 + (148370021/812851200)*n^10 + (33909163/54432000)*n^9 + (455467827113/268240896000)*n^8 + (5892168577/1596672000)*n^7 + (80009607001/12454041600)*n^6 + (31958071429/3592512000)*n^5 + (2175260234977/217945728000)*n^4 + (5539161569/648648000)*n^3 + (6387435643/1029188160)*n^2 + (637969/235620)*n + 1

Example

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

Crossrefs

Sequence in context: A223191 A223807 A223757 * A223871 A223796 A165800

Adjacent sequences: A223842 A223843 A223844 * A223846 A223847 A223848

Keyword

nonn

Author

R. H. Hardin Mar 27 2013

Status

approved