Number of alkyls S C_{n+4} H_{2n+4} with n carbon atoms.

Terms

a(0) =1a(1) =2a(2) =6a(3) =12a(4) =31a(5) =72a(6) =178a(7) =430a(8) =1071a(9) =2654a(10) =6680a(11) =16858a(12) =42926a(13) =109778a(14) =282490a(15) =730028a(16) =1895456a(17) =4940094a(18) =12923600a(19) =33919416a(20) =89301052a(21) =235762572a(22) =624057892a(23) =1655817422a(24) =4403189781a(25) =11733247076a(26) =31326037116a(27) =83786187152a(28) =224475807465