Number of asymmetric polyominoes with n cells.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =5a(5) =20a(6) =84a(7) =316a(8) =1196a(9) =4461a(10) =16750a(11) =62878a(12) =237394a(13) =899265a(14) =3422111a(15) =13069026a(16) =50091095a(17) =192583152a(18) =742560511a(19) =2870523142a(20) =11122817672a(21) =43191285751a(22) =168046076423a(23) =654997492842