Number of 3-noncrossing restricted RNA structures with n vertices.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =5a(5) =14a(6) =40a(7) =119a(8) =364a(9) =1145a(10) =3688a(11) =12139a(12) =40734a(13) =139071a(14) =482214a(15) =1695469a(16) =6036768a(17) =21740969a(18) =79117822a(19) =290674470a(20) =1077306351a(21) =4025068621a(22) =15151115808a(23) =57427176992a(24) =219068962330a(25) =840708048210