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A130622
Number of polyominoes with perimeter at most 2n.
0
0, 1, 2, 5, 11, 36, 122, 538, 2526, 13166, 71153, 400109, 2300430, 13504780, 80547558, 487327904
OFFSET
1,3
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).
Sequence in context: A353210 A295495 A343463 * A112600 A156014 A268397
KEYWORD
hard,more,nonn
AUTHOR
Tanya Khovanova, Aug 10 2007
EXTENSIONS
Offset corrected by John Mason, Jan 16 2023
a(9)-a(16) from John Mason, Jan 16 2023
STATUS
approved