a(n) = A205497(n, floor((n - 1) / 2)). The middle coefficients of the Eulerian zig-zag polynomials.

A373755

a(n) = A205497(n, floor((n - 1) / 2)). The middle coefficients of the Eulerian zig-zag polynomials.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =7a(6) =31a(7) =109a(8) =623a(9) =2951a(10) =20641a(11) =123216a(12) =1019051a(13) =7349140a(14) =70148989a(15) =593513485a(16) =6421463423a(17) =62382094567a(18) =754405836811

External references