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!)
A174084 Number of permutations of length n with no consecutive triples i,...i+r,...i+2r for all r, and for all equal spacings d. 3
21, 94, 544, 3509, 26799, 223123 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,1

COMMENTS

Here we count both the sequence 1,2,3 (r=1) as a progression in 1,2,3,0,4,5, (note d=1) and in 1,0,2,4,3,5 (here, d=2).

LINKS

Table of n, a(n) for n=4..9.

EXAMPLE

For n=4 there are 4!-a(4)=3 with some progression. These are (0,1,2,3), (1,2,3,0), and (3,0,1,2). Here for all the progressions, r=1 and d=1, hence this term is the same as a(4) in A002628.

CROSSREFS

Cf. A002628, A174080, A174085, A174086, A174087.

Sequence in context: A219423 A123213 A296822 * A193218 A220157 A264239

Adjacent sequences:  A174081 A174082 A174083 * A174085 A174086 A174087

KEYWORD

nonn

AUTHOR

Isaac Lambert, Apr 20 2010

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 September 16 05:49 EDT 2021. Contains 347469 sequences. (Running on oeis4.)