Number of monocyclic skeletons with n carbon atoms and a ring size of 6.

Terms

a(0) =1a(1) =1a(2) =5a(3) =12a(4) =40a(5) =106a(6) =317a(7) =868a(8) =2462a(9) =6778a(10) =18801a(11) =51561a(12) =141583a(13) =386865a(14) =1056815a(15) =2880894a(16) =7850318a(17) =21373466a(18) =58182244a(19) =158342918a(20) =430954506a(21) =1173001715a(22) =3193466631a(23) =8696388412a(24) =23689689323a(25) =64555962710a(26) =175989086913a(27) =479971320862