Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A000303
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A000303 Number of permutations of [n] in which the longest run has length 2.
(Formerly M3522 N1430)
+0
2
1, 4, 16, 69, 348, 2016, 13357, 99376, 822040, 7477161, 74207208, 797771520, 9236662345, 114579019468, 1516103040832, 21314681315997 (list; graph; listen)
OFFSET

2,2

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 261, Table 7.4.1.

EXAMPLE

a(3)=4 because we have (13)2, 2(13), (23)1, 3(12), where the parentheses surround runs of length 2.

CROSSREFS

Column 2 of A008304.

Sequence in context: A151243 A006319 A059606 this_sequence A144316 A133789 A151244

Adjacent sequences: A000300 A000301 A000302 this_sequence A000304 A000305 A000306

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

Better description from Emeric Deutsch (deutsch(AT)duke.poly.edu), May 08 2004

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified November 24 23:16 EST 2009. Contains 167481 sequences.


AT&T Labs Research