a(n) is the number of dissections of a convex (n+2)-sided polygon by nonintersecting diagonals into triangles and quadrilaterals such that at least one of the dividing diagonals passes through a chosen vertex.
A380591
a(n) is the number of dissections of a convex (n+2)-sided polygon by nonintersecting diagonals into triangles and quadrilaterals such that at least one of the dividing diagonals passes through a chosen vertex.
Terms
- a(0) =0a(1) =1a(2) =5a(3) =21a(4) =90a(5) =395a(6) =1773a(7) =8110a(8) =37686a(9) =177450a(10) =844935a(11) =4061762a(12) =19687020a(13) =96107358a(14) =472132330a(15) =2332304055a(16) =11578595554a(17) =57736664825a(18) =289055592810
External references
- oeis: A380591