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!)
A229448 Number of 5 X n 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing. 1
17, 47, 128, 324, 753, 1609, 3184, 5890, 10281, 17075, 27176, 41696, 61977, 89613, 126472, 174718, 236833, 315639, 414320, 536444, 685985, 867345, 1085376, 1345402, 1653241, 2015227, 2438232, 2929688, 3497609, 4150613, 4897944, 5749494, 6715825 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = (11/60)*n^5 - (1/2)*n^4 + (15/4)*n^3 - 1*n^2 + (257/30)*n + 6.

Conjectures from Colin Barker, Sep 17 2018: (Start)

G.f.: x*(17 - 55*x + 101*x^2 - 79*x^3 + 44*x^4 - 6*x^5) / (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>6.

(End)

EXAMPLE

Some solutions for n=4:

..0..0..2..2....0..2..2..2....0..0..0..2....0..0..2..2....0..0..2..2

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

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

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

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

PROG

Row 5 of A229445.

CROSSREFS

Sequence in context: A201792 A039949 A220081 * A155841 A147058 A083296

Adjacent sequences:  A229445 A229446 A229447 * A229449 A229450 A229451

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 23 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 May 16 12:19 EDT 2021. Contains 343942 sequences. (Running on oeis4.)