Number of acyclic ketone and aldehyde stereo-isomers with n carbon atoms.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =8a(5) =18a(6) =47a(7) =123a(8) =338a(9) =935a(10) =2657a(11) =7616a(12) =22138a(13) =64886a(14) =191873a(15) =571169a(16) =1711189a(17) =5153883a(18) =15599094a(19) =47415931a(20) =144692886a(21) =443091572a(22) =1361233280a(23) =4194107380a(24) =12957209782a(25) =40128629400a(26) =124562327944a(27) =387467513732