Triangle read by rows: T(n,k) is the number of nonseparable planar maps with 2*n+1 edges and a fixed outer face of 2*k edges which are invariant under a rotation of a 1/2 turn.
A091665
Triangle read by rows: T(n,k) is the number of nonseparable planar maps with 2*n+1 edges and a fixed outer face of 2*k edges which are invariant under a rotation of a 1/2 turn.
Terms
- a(0) =1a(1) =2a(2) =2a(3) =7a(4) =8a(5) =3a(6) =30a(7) =34a(8) =21a(9) =4a(10) =143a(11) =160a(12) =114a(13) =44a(14) =5a(15) =728a(16) =806a(17) =609a(18) =308a(19) =80a(20) =6a(21) =3876a(22) =4256a(23) =3315a(24) =1908a(25) =715a(26) =132a(27) =7a(28) =21318a(29) =23256
External references
- oeis: A091665