Number of palindromic paths starting with 1 through the subset array of {1,2,...,n}; see Comments.

A208655

Number of palindromic paths starting with 1 through the subset array of {1,2,...,n}; see Comments.

Terms

    a(0) =1a(1) =1a(2) =6a(3) =36a(4) =2400a(5) =90000a(6) =55566000a(7) =13553164800

External references