Number of permutations in S_n with major index equal to inversion number.

A207018

Number of permutations in S_n with major index equal to inversion number.

Terms

    a(0) =1a(1) =2a(2) =4a(3) =10a(4) =28a(5) =116a(6) =576a(7) =3634a(8) =26620a(9) =223440a(10) =2100964a(11) =21888712a(12) =250062982a(13) =3108430640

External references