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!)
A224186 Number of n X 4 0..2 arrays with rows unimodal and columns nondecreasing. 1
46, 548, 3526, 15779, 55438, 163746, 424326, 992607, 2138488, 4305730, 8191976, 14853709, 25840868, 43366252, 70515252, 111501861, 171977322, 259398184, 383460946, 556610879, 794633026, 1117333790, 1549321930, 2120898195 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A224190.

LINKS

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

FORMULA

Empirical: a(n) = (41/4032)*n^8 + (55/336)*n^7 + (179/160)*n^6 + (169/40)*n^5 + (615/64)*n^4 + (215/16)*n^3 + (56759/5040)*n^2 + (2173/420)*n + 1.

Conjectures from Colin Barker, Aug 29 2018: (Start)

G.f.: x*(46 + 134*x + 250*x^2 - 91*x^3 + 127*x^4 - 84*x^5 + 36*x^6 - 9*x^7 + x^8) / (1 - x)^9.

a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9.

(End)

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A224190.

Sequence in context: A156892 A224258 A223914 * A027940 A098227 A077732

Adjacent sequences:  A224183 A224184 A224185 * A224187 A224188 A224189

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 01 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 May 24 05:44 EDT 2022. Contains 354005 sequences. (Running on oeis4.)