Number of increasing planar st-graphs with n edges.

Terms

a(0) =1a(1) =1a(2) =3a(3) =9a(4) =33a(5) =131a(6) =561a(7) =2535a(8) =11971a(9) =58579a(10) =295297a(11) =1526427a(12) =8061879a(13) =43380351a(14) =237266225a(15) =1316536991a(16) =7399318871a(17) =42065753191a(18) =241628448517