The number of permutations in S_n with strategic pile of size 3.

A267323

The number of permutations in S_n with strategic pile of size 3.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =3a(4) =12a(5) =66a(6) =432a(7) =3240a(8) =27360

External references