Diagonally symmetric n-celled polyominoes with 1 hole.

Terms

a(0) =1a(1) =0a(2) =5a(3) =4a(4) =20a(5) =18a(6) =79a(7) =84a(8) =304a(9) =332a(10) =1149a(11) =1309a(12) =4312a(13) =5005a(14) =16136a(15) =19049a(16) =60347a(17) =71979a(18) =225867a(19) =271781a(20) =846667a(21) =1025315a(22) =3179798a(23) =3871607a(24) =11966976a(25) =14633947a(26) =45131841a(27) =55395495a(28) =170560833a(29) =210008554