A056881 Number of n-celled diagonally symmetric polyominoes without holes.

0, 0, 1, 0, 2, 2, 6, 5, 21, 18, 70, 61, 239, 206, 828, 711, 2903, 2485, 10314, 8791, 37031, 31451, 134147, 113566, 489672, 413419, 1799084, 1515282, 6647009, 5586834, 24677902, 20703840, 92009606, 77067674, 344336294, 288001040, 1292929699, 1079999410, 4869184237, 4062534430

Offset: 1

Author

N. J. A. Sloane, Sep 03 2000

Keywords

• nonn

Links

• Tomás Oliveira e Silva, Enumeration of polyominoes

Crossrefs

Cf. A000104, A006748 (with holes allowed).

Extensions

a(29)-a(40) from John Mason, Oct 11 2022