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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A224143 Number of n X 5 0..1 arrays with rows and antidiagonals unimodal and columns nondecreasing. 1
16, 86, 275, 691, 1509, 2985, 5471, 9431, 15457, 24285, 36811, 54107, 77437, 108273, 148311, 199487, 263993, 344293, 443139, 563587, 709013, 883129, 1089999, 1334055, 1620113, 1953389, 2339515, 2784555, 3295021, 3877889, 4540615, 5291151, 6137961 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 5 of A224146.

LINKS

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

FORMULA

Empirical: a(n) = (2/15)*n^5 + (2/3)*n^4 + (10/3)*n^3 + (25/3)*n^2 + (203/15)*n - 17 for n>2.

Conjectures from Colin Barker, Aug 27 2018: (Start)

G.f.: x*(16 - 10*x - x^2 + 11*x^3 + 8*x^4 - 10*x^5 + x^6 + x^7) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>8.

(End)

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A224146.

Sequence in context: A252834 A050256 A223835 * A225007 A070052 A203249

Adjacent sequences:  A224140 A224141 A224142 * A224144 A224145 A224146

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 July 22 02:02 EDT 2019. Contains 325210 sequences. (Running on oeis4.)