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

A008988

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

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =97a(6) =579a(7) =3812a(8) =27328a(9) =206410a(10) =1625916a(11) =13241177a(12) =110859326a(13) =950069179a(14) =8307012899a(15) =73908363060a(16) =667683905600

External references