A225013 - OEIS

A225013

Number of 6Xn 0..1 arrays with rows unimodal and columns nondecreasing

7, 49, 252, 1036, 3612, 11088, 30738, 78354, 186142, 416394, 884236, 1794196, 3497248, 6577474, 11980667, 21201211, 36548573, 61520899, 101320712, 163556776, 259187048, 403770544, 619111172, 935394436, 1393938716, 2050706932

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Row 6 of A225010

LINKS

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

FORMULA

Empirical: a(n) = (1/479001600)*n^12 + (1/7257600)*n^11 + (187/43545600)*n^10 + (13/161280)*n^9 + (14671/14515200)*n^8 + (3043/345600)*n^7 + (2380201/43545600)*n^6 + (347911/1451520)*n^5 + (8129699/10886400)*n^4 + (923183/604800)*n^3 + (913741/415800)*n^2 + (49/40)*n + 1

EXAMPLE

Some solutions for n=3

..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..1..0....1..1..0

..0..1..0....0..0..0....0..1..0....0..0..0....0..0..0....0..1..1....1..1..0

..0..1..0....1..0..0....0..1..1....0..1..0....1..0..0....0..1..1....1..1..0

..0..1..0....1..1..0....0..1..1....0..1..0....1..0..0....0..1..1....1..1..0

..1..1..0....1..1..0....1..1..1....0..1..0....1..0..0....0..1..1....1..1..1

..1..1..1....1..1..0....1..1..1....0..1..0....1..0..0....1..1..1....1..1..1

CROSSREFS

Sequence in context: A224150 A094430 A188561 * A228459 A203059 A203383

Adjacent sequences: A225010 A225011 A225012 * A225014 A225015 A225016

KEYWORD

nonn

AUTHOR

R. H. Hardin Apr 23 2013

STATUS

approved