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A263485 revision #7

A263485

Triangle read by rows: T(n,k) (n>=2, 1<=k<=n!) is the number of permutations of n and having k permutations that are greater or equal in (strong) Bruhat order.

1, 1, 1, 2, 0, 2, 0, 1, 1, 3, 0, 5, 0, 2, 0, 4, 0, 0, 0, 4, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 1, 1, 4, 0, 9, 0, 3, 0, 12, 0, 0, 0, 10, 0, 2, 0, 8, 0, 4, 0, 2, 0, 0, 0, 14, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 10, 0, 0, 0, 4, 0, 0, 0, 2, 0, 2, 0, 4, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 1

(list; graph; refs; listen; history; text; internal format)

OFFSET

2,4

COMMENTS

Row sums give A000142, n >= 2.

LINKS

Table of n, a(n) for n=2..101.

FindStat - Combinatorial Statistic Finder, The number of permutations greater than or equal to the given permutation in (strong) Bruhat order.

Wikipedia, Bruhat order

EXAMPLE

Triangle begins:

1,1,