Number of matchings in rooted plane trees on n nodes.

A007859

Number of matchings in rooted plane trees on n nodes.

Terms

    a(0) =0a(1) =1a(2) =4a(3) =18a(4) =84a(5) =405a(6) =2002a(7) =10101a(8) =51844a(9) =269994a(10) =1423784a(11) =7590044a(12) =40846390a(13) =221650195a(14) =1211606190

External references