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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A223571 Number of nX3 0..2 arrays with antidiagonals unimodal 1
27, 729, 16038, 352836, 7762392, 170772624, 3756997728, 82653950016, 1818386900352, 40004511807744, 880099259770368, 19362183714948096, 425968041728858112, 9371296918034878464, 206168532196767326208 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A223576

LINKS

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

FORMULA

Let U(z) = (z^4+6*z^3+23*z^2+18*z+24)/24

a(n) = U(min(n,3))^(max(n,3)-min(n,3)+1) * product{ U(i)^2 , i=1..(min(n,3)-1) }

a(n) = 22*a(n-1) for n>2

EXAMPLE

Some solutions for n=3

..1..2..1....1..2..2....0..1..0....0..1..0....0..2..0....2..0..0....2..1..0

..2..1..1....0..2..2....0..1..2....1..1..2....1..0..2....1..1..1....2..0..2

..2..0..0....2..1..0....1..2..1....2..2..1....1..0..0....1..1..0....1..2..2

CROSSREFS

Sequence in context: A223976 A167726 A268022 * A228973 A171301 A098838

Adjacent sequences:  A223568 A223569 A223570 * A223572 A223573 A223574

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 22 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 November 29 18:41 EST 2021. Contains 349416 sequences. (Running on oeis4.)