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A047884 Triangle of numbers a(n,k) = number of Young tableaux with n cells and k rows (1<=k<=n); also number of self-inverse permutations on n letters in which the length of the longest scattered (i.e. not necessarily contiguous) increasing subsequence is k. 5
1, 1, 1, 1, 2, 1, 1, 5, 3, 1, 1, 9, 11, 4, 1, 1, 19, 31, 19, 5, 1, 1, 34, 92, 69, 29, 6, 1, 1, 69, 253, 265, 127, 41, 7, 1, 1, 125, 709, 929, 583, 209, 55, 8, 1, 1, 251, 1936, 3356, 2446, 1106, 319, 71, 9, 1, 1, 461, 5336, 11626, 10484, 5323, 1904, 461, 89, 10, 1 (list; table; graph; refs; listen; history; internal format)
OFFSET

1,5

REFERENCES

W. Fulton, Young Tableaux, Cambridge, 1997.

D. Stanton and D. White, Constructive Combinatorics, Springer, 1986.

LINKS

Index entries for sequences related to Young tableaux.

R. P. Stanley, A combinatorial miscellany

EXAMPLE

For n=3 the 4 tableaux are

1 2 3 . 1 2 . 1 3 . 1

. . . . 3 . . 2 . . 2

. . . . . . . . . . 3

Triangle begins:

1;

1, 1;

1, 2, 1;

1, 5, 3, 1;

1, 9, 11, 4, 1;

1, 19, 31, 19, 5, 1;

1, 34, 92, 69, 29, 6, 1;

1, 69, 253, 265, 127, 41, 7, 1;

1, 125, 709, 929, 583, 209, 55, 8, 1;

1, 251, 1936, 3356, 2446, 1106, 319, 71, 9, 1;

1, 461, 5336, 11626, 10484, 5323, 1904, 461, 89, 10, 1;

MATHEMATICA

Table[ Plus@@( NumberOfTableaux/@ Reverse/@Union[ Sort/@(Compositions[ n-m, m ]+1) ]), {n, 12}, {m, n} ]

CROSSREFS

Row sums give A000085. Cf. A049400, A049401, and A178249 which imposes contiguity.

Sequence in context: A107735 A137570 A079213 * A124328 A055818 A106240

Adjacent sequences:  A047881 A047882 A047883 * A047885 A047886 A047887

KEYWORD

nonn,tabl,nice,easy

AUTHOR

wouter.meeussen(AT)pandora.be

EXTENSIONS

Definition amended ('scattered' added) by Wouter Meeussen (wouter.meeussen(AT)pandora.be), Dec 22 2010

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Last modified February 17 10:05 EST 2012. Contains 206009 sequences.