OFFSET
1,2
COMMENTS
FORMULA
T(n,k) = (k(n+1)/2 - (k-1)(n-1)/2n) * (n!)^k.
EXAMPLE
Table begins:
1 2 3 4 ...
3 11 32 84 ...
12 132 1152 9072 ...
60 2664 93312 2944512 ...
...
Example: Take the permutations of [2], namely, 12 and 21, and form all possible strings that are concatenations of 2 of these permutations. These are 1212, 1221, 2112, 2121 with 2, 3, 3, 3 increasing runs respectively. T(2,2) = 2 + 3 + 3 + 3 = 11.
CROSSREFS
KEYWORD
AUTHOR
David Scambler, Nov 22 2006
STATUS
approved