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Search: id:A130622
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| A130622 |
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Number of polyominoes with perimeter at most 2n. |
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+0
1
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OFFSET
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0,3
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COMMENT
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The perimeter of a polyomino is always even. a(n) is partial sums of A057730 - Number of polyominoes (A000105) with perimeter 2n. a(n+1) >= A130866(n) - Number of polyominoes (or square animals) with at most n cells.
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CROSSREFS
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Cf. A131482: a(n) is the number of n-celled polyominoes with perimeter 2n+2.
Sequence in context: A080068 A101834 A117758 this_sequence A112600 A092298 A131581
Adjacent sequences: A130619 A130620 A130621 this_sequence A130623 A130624 A130625
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KEYWORD
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hard,more,nonn
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AUTHOR
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Tanya Khovanova (tanyakh(AT)yahoo.com), Aug 10 2007
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