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A167995 Total number of permutations on {1,2,...,n} that have a unique longest increasing subsequence. 4
1, 1, 3, 10, 44, 238, 1506, 10960, 90449, 834166, 8496388, 94738095, 1148207875 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Example: For n=3, 123, 231, and 312 are the only three permutations that have precisely one maximal increasing subsequence.

LINKS

Table of n, a(n) for n=1..13.

Manfred Scheucher, C Code

PROG

(Sage)

print n, len([p for p in permutations(n) if len(p.longest_increasing_subsequences())==1]) # Manfred Scheucher, Jun 06 2015

CROSSREFS

Cf. A167999, A168502.

Sequence in context: A096804 A113059 A240172 * A000608 A259352 A205803

Adjacent sequences:  A167992 A167993 A167994 * A167996 A167997 A167998

KEYWORD

nonn,nice,more

AUTHOR

Anant Godbole, Stephanie Goins, Brad Wild, Nov 16 2009

EXTENSIONS

a(9)-a(13) from Manfred Scheucher, Jun 06 2015

STATUS

approved

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Last modified November 19 05:29 EST 2018. Contains 317333 sequences. (Running on oeis4.)