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A000456 Number of permutations of [n] in which the longest run has length 5.
(Formerly M4735 N2027)
+0
1
1, 10, 99, 1024, 11304, 133669, 1695429, 23023811, 333840443, 5153118154, 84426592621, 1463941342191, 26793750988542, 516319125748337 (list; graph; listen)
OFFSET

5,2

REFERENCES

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

EXAMPLE

a(6)=10 because we have (12346)5, (12356)4, (12456)3, (13456)2, (23456)1, 6(12345), 5(12346), 4(12356), 3(12456), and 2(13456), where the parentheses surround runs of length 5.

CROSSREFS

Cf. A008304.

Adjacent sequences: A000453 A000454 A000455 this_sequence A000457 A000458 A000459

Sequence in context: A081109 A004189 A105694 this_sequence A138365 A119589 A107411

KEYWORD

nonn

AUTHOR

njas

EXTENSIONS

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

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Last modified October 11 13:47 EDT 2008. Contains 144830 sequences.


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