A130622 Number of polyominoes with perimeter at most 2n.

0, 1, 2, 5, 11, 36, 122, 538, 2526, 13166, 71153, 400109, 2300430, 13504780, 80547558, 487327904

Offset: 1

Author

Tanya Khovanova, Aug 10 2007

Keywords

• hard
• more
• nonn

Comments

The perimeter of a polyomino is always even.

a(n) is partial sums of A057730.

a(n+1) >= A130866(n).

Is there another prime term beyond {2, 5, 11}?

Crossrefs

Cf. A131482 (number of n-celled polyominoes with perimeter 2n+2).

Cf. A057730 (number of polyominoes (A000105) with perimeter 2n).

Cf. A130866 (number of polyominoes with at most n cells).

Extensions

Offset corrected by John Mason, Jan 16 2023

a(9)-a(16) from John Mason, Jan 16 2023