A223618 Number of nX6 0..1 arrays with rows and columns unimodal

22, 484, 6504, 57238, 367216, 1856100, 7795951, 28248007, 90732638, 263650284, 703980614, 1748547620, 4079672416, 9012596316, 18975151965, 38281575869, 74344179766, 139521245076, 253869738212, 449160402594, 774624001120

Offset

1,1

Comments

Column 6 of A223620

Links

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

Formula

Empirical: a(n) = (271/5443200)*n^12 + (2327/3326400)*n^11 + (39107/5443200)*n^10 + (1579/36288)*n^9 + (52553/259200)*n^8 + (192371/302400)*n^7 + (8636441/5443200)*n^6 + (56113/20160)*n^5 + (2901677/680400)*n^4 + (523927/113400)*n^3 + (23969/5400)*n^2 + (33487/13860)*n + 1

Example

Some solutions for n=4
..1..1..0..0..0..0....0..0..1..0..0..0....0..0..1..1..1..1....1..1..1..1..1..1
..0..1..0..0..0..0....0..0..0..1..0..0....0..0..1..1..1..1....1..1..1..1..1..1
..0..0..1..0..0..0....0..0..0..1..1..0....0..0..0..1..1..1....0..0..0..1..1..1
..0..0..1..1..0..0....1..1..0..0..0..0....0..0..0..0..1..1....0..0..0..1..1..1

Crossrefs

Sequence in context: A223720 A223667 A223826 * A223678 A223784 A223970

Adjacent sequences: A223615 A223616 A223617 * A223619 A223620 A223621

Keyword

nonn

Author

R. H. Hardin Mar 24 2013

Status

approved