A224263 Number of 3Xn 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing

10, 100, 648, 3096, 12032, 40182, 119367, 322885, 808618, 1898050, 4215105, 8921265, 18101023, 35375831, 66857059, 122591129, 218705294, 380533212, 647088610, 1077366434, 1759087854, 2820672704, 4447425227, 6903161705

Offset

1,1

Comments

Row 3 of A224262

Links

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

Formula

Empirical: a(n) = (1/19160064)*n^12 + (1/1064448)*n^11 + (181/6220800)*n^10 + (557/1451520)*n^9 + (13571/2903040)*n^8 + (3197/96768)*n^7 + (8451841/43545600)*n^6 + (316789/483840)*n^5 + (535159/311040)*n^4 + (151169/72576)*n^3 + (9281749/1663200)*n^2 - (73057/13860)*n + 5

Example

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

Crossrefs

Sequence in context: A364342 A208074 A092707 * A223920 A223865 A366669

Adjacent sequences: A224260 A224261 A224262 * A224264 A224265 A224266

Keyword

nonn

Author

R. H. Hardin Apr 02 2013

Status

approved