A246982 Triangle read by rows: T(n,k) = maximal number of inversions among all k-sorted permutations on n letters (n>=2, 1<=k<=n-1).

1, 1, 3, 2, 4, 6, 2, 4, 8, 10, 3, 6, 9, 13, 15, 3, 7, 9, 15, 19, 21, 4, 8, 12, 16, 22, 26, 28, 4, 9, 14, 16, 24, 30, 34, 36, 5, 10, 16, 20, 25, 33, 39, 43, 45, 5, 11, 17, 23, 25, 35, 43, 49, 53, 55, 6, 12, 18, 26, 30, 36, 46, 54, 60, 64, 66, 6, 13, 20

Offset

2,3

Links

Table of n, a(n) for n=2..70.

Example

Triangle begins:
1,
1,3,
2,4,6,
2,4,8,10,
3,6,9,13,15,
3,7,9,15,19,21,
4,8,12,16,22,26,28,
4,9,14,16,24,30,34,36,
5,10,16,20,25,33,39,43,45,
5,11,17,23,25,35,43,49,53,55,
...

Crossrefs

A034856 is a diagonal.

Sequence in context: A264993 A280318 A353659 * A258215 A319073 A129601

Adjacent sequences: A246979 A246980 A246981 * A246983 A246984 A246985

Keyword

nonn,tabl

Author

N. J. A. Sloane, Sep 14 2014

Status

approved