Number of irreducible indecomposable spherical curves with n crossings (only ordinary double points), the circle is not oriented, the sphere is not oriented (UU case).

A264759

Number of irreducible indecomposable spherical curves with n crossings (only ordinary double points), the circle is not oriented, the sphere is not oriented (UU case).

Terms

    a(0) =0a(1) =0a(2) =1a(3) =1a(4) =2a(5) =3a(6) =10a(7) =27a(8) =101a(9) =364a(10) =1610a(11) =7202a(12) =34659a(13) =170692a(14) =864590a(15) =4463287a(16) =23415443a(17) =124526110a(18) =670224294a(19) =3644907768a(20) =20011145443a(21) =110794212315a(22) =618187581204

External references