Number of free polyquarcs with n cells.

Terms

a(0) =1a(1) =2a(2) =4a(3) =13a(4) =38a(5) =141a(6) =521a(7) =2064a(8) =8155a(9) =33111a(10) =135271a(11) =559215a(12) =2324502a(13) =9726175a(14) =40887925a(15) =172669360a(16) =731895102a(17) =3112855720