Number of rooted planar maps with 4 vertices and n faces and no isthmuses.
A006421
Number of rooted planar maps with 4 vertices and n faces and no isthmuses.
Terms
- a(0) =1a(1) =30a(2) =449a(3) =4795a(4) =41850a(5) =319320a(6) =2213665a(7) =14283280a(8) =87169790a(9) =508887860a(10) =2865204762a(11) =15654301865a(12) =83388235348a(13) =434685964540
External references
- oeis: A006421