Number of immersions of oriented circle into oriented sphere with n labeled double points.

A268567

Number of immersions of oriented circle into oriented sphere with n labeled double points.

Terms

    a(0) =1a(1) =4a(2) =42a(3) =780a(4) =21552a(5) =803760a(6) =38054160a(7) =2194345440a(8) =149604053760

External references