Number of ways to place non-crossing diagonals in convex (n+4)-gon so as to create no triangles or quadrilaterals.

A054514

Number of ways to place non-crossing diagonals in convex (n+4)-gon so as to create no triangles or quadrilaterals.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =5a(4) =10a(5) =16a(6) =45a(7) =109a(8) =222a(9) =540a(10) =1341a(11) =3065a(12) =7328a(13) =18112a(14) =43530a(15) =105390a(16) =260254a(17) =639244a(18) =1570257a(19) =3893805a(20) =9669236a(21) =24014264a(22) =59903650a(23) =149806494a(24) =374982790a(25) =940835404a(26) =2365679689a(27) =5955973237a(28) =15018854005a(29) =37935575685

External references