Number of matchings in the n-double cone graph.

Terms

a(0) =3a(1) =21a(2) =64a(3) =217a(4) =671a(5) =2052a(6) =6119a(7) =18001a(8) =52288a(9) =150429a(10) =429243a(11) =1216516a(12) =3427659a(13) =9609357a(14) =26821696a(15) =74576737a(16) =206650199a(17) =570877956a(18) =1572754223a(19) =4322192329a(20) =11851475008a(21) =32430381861a(22) =88576465779a(23) =241511251972a(24) =657457204371