Number of n-celled polyominoes without holes, symmetric about axis 2.

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =3a(7) =4a(8) =4a(9) =6a(10) =10a(11) =11a(12) =16a(13) =18a(14) =33a(15) =34a(16) =56a(17) =56a(18) =110a(19) =106a(20) =193a(21) =177a(22) =372a(23) =335a(24) =662a(25) =571a(26) =1269a(27) =1084a(28) =2282a(29) =1875