The number of pairs of permutations in the product group S_n X S_n with k common descents, n >= 1 and 0 <= k <= n-1.
A192721
The number of pairs of permutations in the product group S_n X S_n with k common descents, n >= 1 and 0 <= k <= n-1.
Terms
- a(0) =1a(1) =3a(2) =1a(3) =19a(4) =16a(5) =1a(6) =211a(7) =299a(8) =65a(9) =1a(10) =3651a(11) =7346a(12) =3156a(13) =246a(14) =1a(15) =90921a(16) =237517a(17) =160322a(18) =28722a(19) =917a(20) =1a(21) =3081513a(22) =9903776a(23) =9302567a(24) =2864912a(25) =245407a(26) =3424a(27) =1a(28) =136407699a(29) =520507423
External references
- oeis: A192721