OFFSET
1,2
COMMENTS
At first equal to and eventually greater than corresponding entry of A195924, number of fixed points of Foata's bijection.
For any large n, the two permutations with maj and inv both 2 are 2314..n, and 14235..n.
LINKS
Joerg Arndt, C++ program to compute terms.
EXAMPLE
A(4)=10: the 10 permutations of 4 elements with major index equal to inversion number are
#: perm #inv. inversion table
1: [ 0 1 2 3 ] 0 [ 0 0 0 ]
2: [ 0 3 1 2 ] 2 [ 0 2 0 ]
3: [ 1 0 2 3 ] 1 [ 0 0 1 ]
4: [ 1 2 0 3 ] 2 [ 0 1 1 ]
5: [ 1 2 3 0 ] 3 [ 1 1 1 ]
6: [ 2 1 0 3 ] 3 [ 0 1 2 ]
7: [ 2 1 3 0 ] 4 [ 1 1 2 ]
8: [ 2 3 1 0 ] 5 [ 1 2 2 ]
9: [ 3 0 2 1 ] 4 [ 1 0 3 ]
10: [ 3 2 1 0 ] 6 [ 1 2 3 ]
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
William J. Keith, Feb 14 2012
EXTENSIONS
a(14) by Joerg Arndt, Sep 29 2012.
STATUS
approved