login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A266357 Number of n X 3 binary arrays with rows and columns lexicographically nondecreasing and row and column sums nondecreasing. 1
4, 13, 35, 82, 173, 337, 614, 1060, 1749, 2777, 4266, 6369, 9273, 13206, 18441, 25302, 34170, 45490, 59776, 77620, 99698, 126778, 159728, 199525, 247262, 304159, 371571, 450998, 544095, 652683, 778758, 924504, 1092303, 1284747, 1504650, 1755061 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 5*a(n-1) -9*a(n-2) +6*a(n-3) -6*a(n-7) +9*a(n-8) -5*a(n-9) +a(n-10).

Empirical g.f.: x*(4 - 7*x + 6*x^2 - 6*x^6 + 9*x^7 - 5*x^8 + x^9) / ((1 - x)^7*(1 + x)*(1 + x + x^2)). - Colin Barker, Jan 09 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 3 of A266362.

Sequence in context: A089453 A057159 A189588 * A095941 A210843 A177155

Adjacent sequences:  A266354 A266355 A266356 * A266358 A266359 A266360

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 28 2015

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 January 18 13:49 EST 2020. Contains 331010 sequences. (Running on oeis4.)