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A308982
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Areas of integer rectangles circumscribed by increasingly large circles.
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0
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1, 2, 4, 3, 6, 4, 9, 8, 12, 5, 10, 16, 15, 6, 12, 20, 18, 7, 25, 24, 14, 21, 30, 8, 28, 16, 36, 24, 35, 32, 9, 18, 42, 40, 27, 36, 49, 48, 10, 20, 45, 30, 56, 40, 54, 11, 22, 50, 64, 33, 63, 60, 44, 12, 72, 55, 24, 70, 36, 66, 48, 81, 80, 60, 13, 77, 26, 39
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OFFSET
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1,2
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COMMENTS
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Sort all rectangles with integer side lengths by the radius of the circle that circumscribes them. Ties are broken by sorting by area. The terms of the sequence are the areas of the rectangles.
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LINKS
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Table of n, a(n) for n=1..68.
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EXAMPLE
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a(1) is a 1 X 1 rectangle; r = sqrt(1^2 + 1^2) = sqrt(2); A = 1.
a(2) is a 2 X 1 rectangle; r = sqrt(2^2 + 1^2) = sqrt(5); A = 2.
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MATHEMATICA
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Times @@@ Take[Flatten[ SortBy[#, Times @@ # &] & /@ GatherBy[ SortBy[ Union[Sort /@ Tuples[ Range[70], 2]], Total[#^2] &], Total[#^2] &], 1], 70] (* Giovanni Resta, Jul 18 2019 *)
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CROSSREFS
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Cf. A024509.
Sequence in context: A151734 A175027 A269837 * A182298 A182732 A119477
Adjacent sequences: A308979 A308980 A308981 * A308983 A308984 A308985
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KEYWORD
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nonn
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AUTHOR
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Dave Rutt, Jul 04 2019
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EXTENSIONS
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More terms from Giovanni Resta, Jul 17 2019
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STATUS
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approved
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