Number of immersions of unoriented circle into oriented sphere with n labeled double points, where additionally each double point distinguishes one of the 4 half-edges incident to it.

A268557

Number of immersions of unoriented circle into oriented sphere with n labeled double points, where additionally each double point distinguishes one of the 4 half-edges incident to it.

Terms

    a(0) =2a(1) =32a(2) =1344a(3) =99840a(4) =11034624a(5) =1646100480a(6) =311739678720

External references