// output of ./demo/seq/A207018-demo.cc:
// Description:
//% OEIS sequence A207018:
//% Number of permutations with major index equal to inversion number.

arg 1: 5 == n  [Permutations of n elements (n>=2)]  default=5
   1:    [ 0 1 2 3 4 ]   0    [ 0 0 0 0 ]
   2:    [ 0 2 4 1 3 ]   3    [ 0 2 1 0 ]
   3:    [ 0 3 1 2 4 ]   2    [ 0 0 2 0 ]
   4:    [ 0 4 3 1 2 ]   5    [ 0 2 3 0 ]
   5:    [ 1 0 2 3 4 ]   1    [ 0 0 0 1 ]
   6:    [ 1 2 0 3 4 ]   2    [ 0 0 1 1 ]
   7:    [ 1 2 3 0 4 ]   3    [ 0 1 1 1 ]
   8:    [ 1 2 3 4 0 ]   4    [ 1 1 1 1 ]
   9:    [ 1 4 2 0 3 ]   5    [ 0 1 3 1 ]
  10:    [ 1 4 2 3 0 ]   6    [ 1 1 3 1 ]
  11:    [ 2 0 4 1 3 ]   4    [ 0 2 0 2 ]
  12:    [ 2 1 0 3 4 ]   3    [ 0 0 1 2 ]
  13:    [ 2 1 3 0 4 ]   4    [ 0 1 1 2 ]
  14:    [ 2 1 3 4 0 ]   5    [ 1 1 1 2 ]
  15:    [ 2 3 1 0 4 ]   5    [ 0 1 2 2 ]
  16:    [ 2 3 1 4 0 ]   6    [ 1 1 2 2 ]
  17:    [ 2 3 4 1 0 ]   7    [ 1 2 2 2 ]
  18:    [ 2 4 0 3 1 ]   6    [ 1 0 3 2 ]
  19:    [ 3 0 2 1 4 ]   4    [ 0 1 0 3 ]
  20:    [ 3 0 2 4 1 ]   5    [ 1 1 0 3 ]
  21:    [ 3 2 1 0 4 ]   6    [ 0 1 2 3 ]
  22:    [ 3 2 1 4 0 ]   7    [ 1 1 2 3 ]
  23:    [ 3 2 4 1 0 ]   8    [ 1 2 2 3 ]
  24:    [ 3 4 2 1 0 ]   9    [ 1 2 3 3 ]
  25:    [ 4 0 1 3 2 ]   5    [ 1 0 0 4 ]
  26:    [ 4 1 3 2 0 ]   8    [ 1 2 1 4 ]
  27:    [ 4 2 0 3 1 ]   7    [ 1 0 2 4 ]
  28:    [ 4 3 2 1 0 ]  10    [ 1 2 3 4 ]
 ct=28