Number of matchings in the n-trapezohedral graph.

Terms

a(0) =2a(1) =6a(2) =27a(3) =108a(4) =399a(5) =1398a(6) =4714a(7) =15438a(8) =49407a(9) =155196a(10) =480027a(11) =1465566a(12) =4425122a(13) =13233678a(14) =39246459a(15) =115536348a(16) =337905279a(17) =982497918a(18) =2841742762a(19) =8180378886a(20) =23446955727a(21) =66940332876a(22) =190423667067a(23) =539897845398