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!)
A141825 Encodes permutations which "avoid" the subsequence "123" based on the mapping described in A051683. 0
0, 1, 2, 3, 4, 6, 7, 8, 9, 10, 12, 13, 16, 18, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 36, 37, 40, 42, 48, 49, 50, 51, 52, 60, 61, 64, 66, 72, 73, 76, 90, 96 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Note that a(n) can be viewed as an irregular table with shape sequence 1 1 3 9 28 ... demonstrating the relationships with 1 2 5 14 42 ... Cf. A000108 and A000142.
0
1
2 3 4
6 7 8 9 10 12 13 16 18
24 25 26 27 28 30 31 32 ... 96
120 ...
LINKS
EXAMPLE
The numbers 0 thru 4 map to 321,312,231,213 and 132 and are included because they avoid 123. The next number, 5, maps to 123 so is excluded from a(n).
CROSSREFS
Sequence in context: A260816 A285598 A275804 * A238369 A296858 A296241
KEYWORD
more,nonn
AUTHOR
Alford Arnold, Jul 24 2008
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 March 4 13:38 EST 2024. Contains 370532 sequences. (Running on oeis4.)