Number of sensed planar maps with n vertices and 2 faces.

Terms

a(0) =1a(1) =2a(2) =5a(3) =14a(4) =42a(5) =140a(6) =473a(7) =1670a(8) =5969a(9) =21679a(10) =79419a(11) =293496a(12) =1091006a(13) =4078213a(14) =15312150a(15) =57721030a(16) =218333832a(17) =828408842a(18) =3151769615a(19) =12020870753a(20) =45949957412a(21) =176001205559a(22) =675384194565