Alkane systems (see Cyvin reference for precise definition).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =10a(6) =24a(7) =67a(8) =182a(9) =527a(10) =1494a(11) =4351a(12) =12548a(13) =36561a(14) =105962a(15) =308432a(16) =894941a(17) =2602128a(18) =7549318