Number of n-celled rotationally symmetric polyominoes without holes.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =5a(6) =4a(7) =18a(8) =19a(9) =72a(10) =72a(11) =268a(12) =276a(13) =1002a(14) =1043a(15) =3733a(16) =3926a(17) =14000a(18) =14810a(19) =52658a(20) =55987a(21) =199020a(22) =212364a(23) =754826a(24) =807861a(25) =2872926a(26) =3082202a(27) =10966333a(28) =11789248a(29) =41970489