Number of immersions of an unoriented circle into the oriented sphere with n double points.
A008987
Number of immersions of an unoriented circle into the oriented sphere with n double points.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =99a(6) =588a(7) =3829a(8) =27404a(9) =206543a(10) =1626638a(11) =13242275a(12) =110865868a(13) =950078474a(14) =8307074080a(15) =73908443799a(16) =667684486429
External references
- oeis: A008987