Arises in enumeration of locally convex functions.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =14a(5) =24a(6) =40a(7) =66a(8) =106a(9) =170a(10) =270a(11) =426a(12) =668a(13) =1044a(14) =1626a(15) =2526a(16) =3914a(17) =6054a(18) =9352a(19) =14428a(20) =22236a(21) =34244a(22) =52704a(23) =81070a(24) =12465a(25) =191594a(26) =294410a(27) =452298a(28) =694734a(29) =1066968