Number of matchings in the C_n X P_2 (n-prism) graph.

Terms

a(0) =2a(1) =12a(2) =32a(3) =108a(4) =342a(5) =1104a(6) =3544a(7) =11396a(8) =36626a(9) =117732a(10) =378424a(11) =1216380a(12) =3909830a(13) =12567448a(14) =40395792a(15) =129844996a(16) =417363330a(17) =1341539196a(18) =4312135920a(19) =13860583628a(20) =44552347606a(21) =143205490528a(22) =460308235560