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A130866
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Number of polyominoes (or square animals) with at most n cells.
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9
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1, 2, 4, 9, 21, 56, 164, 533, 1818, 6473, 23546, 87146, 325737, 1227708, 4654284, 17733539, 67841448, 260463500, 1003087732, 3873759682, 14996820360, 58188678048, 226235685776, 881235386179, 3438462430943, 13437551253018
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OFFSET
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1,2
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COMMENTS
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The sequence excludes the null polyomino of size 0. - John Mason, Jan 10 2023
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LINKS
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FORMULA
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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