Alkane systems (see Cyvin reference for precise definition).

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =6a(5) =18a(6) =44a(7) =129a(8) =354a(9) =1040a(10) =2961a(11) =8662a(12) =25022a(13) =73005a(14) =211723a(15) =616522a(16) =1789320a(17) =5203258a(18) =15097067