A223684 Number of 6Xn 0..1 arrays with rows and antidiagonals unimodal

64, 4096, 83737, 744272, 4106403, 17068664, 58944337, 178002044, 484800960, 1215412314, 2845433373, 6286999243, 13216899344, 26605753969, 51547601046, 96528061541, 175319673499, 309757515173, 533729732564, 898819275234

Offset

1,1

Comments

Row 6 of A223680

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 + (44081/1360800)*n^10 + (67031/362880)*n^9 + (1007557/226800)*n^8 + (1582/675)*n^7 + (211210703/1360800)*n^6 - (60265871/120960)*n^5 + (11265884461/5443200)*n^4 - (118533836/14175)*n^3 + (2826245099/151200)*n^2 - (113088191/3960)*n + 23503 for n>3

Example

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

Crossrefs

Sequence in context: A189693 A188744 A188996 * A189068 A189193 A188878

Adjacent sequences: A223681 A223682 A223683 * A223685 A223686 A223687

Keyword

nonn

Author

R. H. Hardin Mar 25 2013

Status

approved