Sum of the path lengths of all binary trees with n edges.

Terms

a(0) =0a(1) =2a(2) =14a(3) =74a(4) =352a(5) =1588a(6) =6946a(7) =29786a(8) =126008a(9) =527900a(10) =2195580a(11) =9080772a(12) =37392864a(13) =153434536a(14) =627778954a(15) =2562441466a(16) =10438340104a(17) =42449348236a(18) =172376641924a(19) =699100282156