A224261 Number of n X 7 0..2 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.

239, 9503, 119367, 850875, 4542734, 20568693, 83124099, 306179180, 1038489172, 3266157979, 9583669559, 26387428383, 68551067596, 168889679757, 396460357949, 890533215416, 1921389717480, 3995624313351, 8033215042947, 15657425192703, 29658055171558, 54715516508103

Offset

1,1

Links

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

Formula

Empirical: a(n) = (118519/21794572800)*n^14 + (2257/124540416)*n^13 + (11489/13305600)*n^12 + (227251/47900160)*n^11 + (39637/777600)*n^10 + (458077/1451520)*n^9 + (169757921/76204800)*n^8 + (6354631/870912)*n^7 + (526598447/7257600)*n^6 + (85059797/2177280)*n^5 + (6141145069/8553600)*n^4 - (2165544719/1995840)*n^3 - (174076430267/75675600)*n^2 - (921446093/36036)*n + 109916 for n>8.

Example

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

Crossrefs

Column 7 of A224262.

Sequence in context: A065750 A201045 A056095 * A223917 A224189 A223932

Adjacent sequences: A224258 A224259 A224260 * A224262 A224263 A224264

Keyword

nonn

Author

R. H. Hardin, Apr 02 2013

Extensions

Name corrected by Andrew Howroyd, Mar 18 2025

Status

approved