Number of nodes of even outdegree (including leaves) in all ordered trees with n edges.

A026641

Number of nodes of even outdegree (including leaves) in all ordered trees with n edges.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =13a(4) =46a(5) =166a(6) =610a(7) =2269a(8) =8518a(9) =32206a(10) =122464a(11) =467842a(12) =1794196a(13) =6903352a(14) =26635774a(15) =103020253a(16) =399300166a(17) =1550554582a(18) =6031074184a(19) =23493410758a(20) =91638191236a(21) =357874310212

External references