login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A224147 Number of 3 X n 0..1 arrays with rows and antidiagonals unimodal and columns nondecreasing. 1
4, 16, 49, 124, 275, 554, 1037, 1831, 3082, 4984, 7789, 11818, 17473, 25250, 35753, 49709, 67984, 91600, 121753, 159832, 207439, 266410, 338837, 427091, 533846, 662104, 815221, 996934, 1211389, 1463170, 1757329, 2099417, 2495516, 2952272 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A224146.

LINKS

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

FORMULA

Empirical: a(n) = (1/720)*n^6 + (1/80)*n^5 + (23/144)*n^4 + (29/48)*n^3 + (241/180)*n^2 + (53/60)*n + 1.

Conjectures from Colin Barker, Aug 28 2018: (Start)

G.f.: x*(4 - 12*x + 21*x^2 - 23*x^3 + 16*x^4 - 6*x^5 + x^6) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A224146.

Sequence in context: A119005 A237986 A086601 * A227266 A114185 A188516

Adjacent sequences:  A224144 A224145 A224146 * A224148 A224149 A224150

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 31 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 21 23:55 EDT 2019. Contains 327286 sequences. (Running on oeis4.)