Number of bicolored maps defined by immersions of unoriented circle into oriented sphere with n double points with edges labeled 1..2*n such that labels of successive edges along the curve (starting at any edge, going in the direction determined by the coloring) are encountered in pairs of the form {2*m-1, 2*m} (in either order).
A268560
Number of bicolored maps defined by immersions of unoriented circle into oriented sphere with n double points with edges labeled 1..2*n such that labels of successive edges along the curve (starting at any edge, going in the direction determined by the coloring) are encountered in pairs of the form {2*m-1, 2*m} (in either order).
Terms
- a(0) =2a(1) =16a(2) =336a(3) =12480a(4) =689664a(5) =51440640a(6) =4870932480a(7) =561752432640
External references
- oeis: A268560