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Search: id:A051302
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| A051302 |
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Numbers whose square can be expressed as the sum of two positive cubes in more than one way. |
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| 77976, 223587, 623808, 894348, 1788696, 2105352, 2989441, 4298427, 4672423, 4990464, 5986575, 6036849, 7154784, 8437832, 9747000, 14309568, 16842816, 23915528, 24147396, 24770529, 26745768, 27948375, 34387416, 34634719
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Observations regarding terms through a(64)=306761364: - All are multiples of 7^2, 13^2, and/or 19^2. - Other than 2, 3, 5, and 11, their only prime factors are 7, 13, 19, 31, 43, 61, 67, 79, 127, 151, and 181 (each of which exceeds a multiple of 6 by 1). - None is a cube or higher power; the ones that are squares are a(7), a(12), a(17), a(19), a(20), a(32), a(33), a(41), a(49), a(55), and a(58). - Jon E. Schoenfield (jonscho(AT)hiwaay.net), Oct 08 2006
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LINKS
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Jon Schoenfield, Table of n, a(n) for n = 1..64
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EXAMPLE
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2989441^2 = 1729^3+20748^3 = 15561^3+17290^3, so 2989441 is in the sequence.
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CROSSREFS
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Cf. A050801, A001235, A011541.
Sequence in context: A133973 A133974 A061528 this_sequence A016819 A016855 A016975
Adjacent sequences: A051299 A051300 A051301 this_sequence A051303 A051304 A051305
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KEYWORD
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nonn,nice
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AUTHOR
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Jud McCranie (j.mccranie(AT)comcast.net)
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EXTENSIONS
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Definition corrected by Jon Schoenfield, Aug 27 2006
More terms from Jon E. Schoenfield (jonscho(AT)hiwaay.net), Oct 08 2006
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