login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A223963 Number of 3 X n 0..3 arrays with antidiagonals unimodal and rows and diagonals nondecreasing. 1
64, 707, 3471, 12311, 36028, 92734, 217144, 471994, 965172, 1874532, 3482781, 6225291, 10754192, 18022648, 29393806, 46779538, 72814768, 111073890, 166336539, 244910775, 355022580, 507281450, 715232788, 996008770, 1371090364 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Row 3 of A223961.
LINKS
FORMULA
Empirical: a(n) = (1/8640)*n^9 + (1/320)*n^8 + (503/10080)*n^7 + (659/1440)*n^6 + (3013/960)*n^5 + (37141/2880)*n^4 + (106019/2160)*n^3 - (18977/720)*n^2 + (2711/70)*n - 6 for n>2.
Conjectures from Colin Barker, Aug 24 2018: (Start)
G.f.: x*(64 + 67*x - 719*x^2 + 1736*x^3 - 2287*x^4 + 2271*x^5 - 2070*x^6 + 1632*x^7 - 910*x^8 + 311*x^9 - 58*x^10 + 5*x^11) / (1 - x)^10.
a(n) = 10*a(n-1) - 45*a(n-2) + 120*a(n-3) - 210*a(n-4) + 252*a(n-5) - 210*a(n-6) + 120*a(n-7) - 45*a(n-8) + 10*a(n-9) - a(n-10) for n>12.
(End)
EXAMPLE
Some solutions for n=3:
..0..0..1....2..2..2....0..0..2....0..0..2....0..2..3....0..1..3....1..2..2
..1..1..1....1..2..2....0..2..3....1..1..1....0..1..3....1..2..3....0..1..3
..0..1..3....1..1..3....3..3..3....1..1..2....0..0..2....1..1..3....0..0..2
CROSSREFS
Cf. A223961.
Sequence in context: A119287 A318023 A320408 * A372844 A303726 A305229
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 29 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 17 18:28 EDT 2024. Contains 374377 sequences. (Running on oeis4.)