Number of alkyls X^{II} C_n H_{2n+1} Y with n carbon atoms.

Terms

a(0) =1a(1) =2a(2) =4a(3) =10a(4) =25a(5) =64a(6) =166a(7) =437a(8) =1157a(9) =3087a(10) =8276a(11) =22287a(12) =60230a(13) =163284a(14) =443820a(15) =1209155a(16) =3300890a(17) =9027337a(18) =24727437a(19) =67829684a(20) =186302693a(21) =512301120a(22) =1410237805a(23) =3885803531a(24) =10716571591a(25) =29579231200a(26) =81704634803a(27) =225845362116