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A178937
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Partial sums of number of different shapes formed by bending a piece of wire of length n in the plane A066372.
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0
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1, 2, 4, 7, 12, 20, 35, 58, 101, 172, 300, 509, 888, 1538, 2683, 4611, 8033, 13941, 24236, 41766, 72504, 125592, 217563, 374757, 648378, 1120243, 1934800, 3328622, 5743517, 9901009, 17061027, 29314809, 50478219, 86859244, 149408560, 256438542, 440869300
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OFFSET
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1,2
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COMMENTS
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Number of different shapes formed by bending (+ or - 90 degrees at each bend) a piece of wire of length <= n in the plane.
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LINKS
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EXAMPLE
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a(9) = 1 + 1 + 2 + 3 + 5 + 8 + 15 + 23 + 43 = 101 is prime. The next prime is a(15) = 2683.
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MATHEMATICA
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CROSSREFS
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KEYWORD
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nonn,walk
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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