Number of matchings in the n-dipyramidal graph.

Terms

a(0) =2a(1) =3a(2) =9a(3) =22a(4) =51a(5) =111a(6) =234a(7) =477a(8) =951a(9) =1858a(10) =3573a(11) =6777a(12) =12706a(13) =23583a(14) =43389a(15) =79214a(16) =143631a(17) =258843a(18) =463914a(19) =827337a(20) =1468827a(21) =2597018a(22) =4574529a(23) =8030037a(24) =14050946a(25) =24514011a(26) =42651729a(27) =74021062a(28) =128157771a(29) =221397543