Number of polyominoes of n cells with both diagonal symmetries, for which the 180-degree rotational symmetry has an axis that coincides with the center of a square, but without 90-degree rotational symmetry.

A351159

Number of polyominoes of n cells with both diagonal symmetries, for which the 180-degree rotational symmetry has an axis that coincides with the center of a square, but without 90-degree rotational symmetry.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =0a(8) =0a(9) =0a(10) =2a(11) =1a(12) =3a(13) =1a(14) =6a(15) =4a(16) =9a(17) =6a(18) =20a(19) =19a(20) =32a(21) =25a(22) =64a(23) =82a(24) =114a(25) =107a(26) =217a(27) =332a(28) =397a(29) =442

External references