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!)
A332748 The number of permutations of {1,1,1,2,2,2,...,n,n,n} with the property that b(1) >= b(2) >= ... >= b(n) (Three k's are skipped by b(k) for k=1..n). 2
1, 1, 4, 18, 124, 738, 7464, 55890, 668778, 7030210 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..9.

EXAMPLE

In case of n = 1.

     |           | b(1)

-----+-----------+------

   1 | [1, 1, 1] | [0] *

In case of n = 2.

     |                    | b(1),b(2)

-----+--------------------+----------

   1 | [2, 2, 2, 1, 1, 1] | [0, 0]

   2 | [2, 1, 2, 1, 2, 1] | [1, 1]

   3 | [1, 2, 1, 2, 1, 2] | [1, 1]

   4 | [1, 1, 1, 2, 2, 2] | [0, 0]

In case of n = 3.

     |                             | b(1),b(2),b(3)

-----+-----------------------------+---------------

   1 | [3, 3, 3, 2, 2, 2, 1, 1, 1] | [0, 0, 0]

   2 | [3, 3, 3, 2, 1, 2, 1, 2, 1] | [1, 1, 0]

   3 | [3, 3, 3, 1, 2, 1, 2, 1, 2] | [1, 1, 0]

   4 | [3, 3, 3, 1, 1, 1, 2, 2, 2] | [0, 0, 0]

   5 | [3, 2, 1, 3, 2, 1, 3, 2, 1] | [2, 2, 2]

   6 | [3, 1, 2, 3, 1, 2, 3, 1, 2] | [2, 2, 2]

   7 | [1, 3, 3, 3, 1, 2, 2, 2, 1] | [3, 0, 0]

   8 | [2, 3, 1, 2, 3, 1, 2, 3, 1] | [2, 2, 2]

   9 | [1, 3, 2, 1, 3, 2, 1, 3, 2] | [2, 2, 2]

  10 | [2, 1, 3, 2, 1, 3, 2, 1, 3] | [2, 2, 2]

  11 | [1, 2, 3, 1, 2, 3, 1, 2, 3] | [2, 2, 2]

  12 | [2, 2, 2, 3, 3, 3, 1, 1, 1] | [0, 0, 0]

  13 | [1, 1, 1, 3, 3, 3, 2, 2, 2] | [0, 0, 0]

  14 | [1, 2, 2, 2, 1, 3, 3, 3, 1] | [3, 0, 0]

  15 | [2, 2, 2, 1, 1, 1, 3, 3, 3] | [0, 0, 0]

  16 | [2, 1, 2, 1, 2, 1, 3, 3, 3] | [1, 1, 0]

  17 | [1, 2, 1, 2, 1, 2, 3, 3, 3] | [1, 1, 0]

  18 | [1, 1, 1, 2, 2, 2, 3, 3, 3] | [0, 0, 0]

* (strongly decreasing)

CROSSREFS

Cf. A059108, A261516 (strongly decreasing), A322178, A332752.

Sequence in context: A292500 A228065 A317377 * A215691 A073511 A108704

Adjacent sequences:  A332745 A332746 A332747 * A332749 A332750 A332751

KEYWORD

nonn,more

AUTHOR

Seiichi Manyama, Feb 21 2020

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 April 20 18:08 EDT 2021. Contains 343135 sequences. (Running on oeis4.)