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Search: id:A051388
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| A051388 |
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Numbers whose 4th power can be expressed as the sum of two positive cubes in more than one way. |
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+0 1
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| 1729, 2457, 4104, 4914, 4977, 8001, 8216, 10773, 13832, 15561, 16263, 19656, 20683, 32832, 39312, 39816, 40033, 46683, 64008, 64232, 65728, 66339, 80236, 86184
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(25) > 10^5. [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 03 2009]
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EXAMPLE
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1729^4 = 1729^3+20748^3 = 15561^3+17290^3
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PROGRAM
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(PARI) for(i=1, 10^5, x=i^4; c=0; for(j=1, floor(sqrtn(x/2, 3)), if(ispower(x-j^3, 3), c++)); if(c>1, print(i" "c))) [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 03 2009]
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CROSSREFS
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Cf. A051386, A051387.
Sequence in context: A112140 A044883 A154717 this_sequence A033181 A154729 A083737
Adjacent sequences: A051385 A051386 A051387 this_sequence A051389 A051390 A051391
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KEYWORD
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more,nonn
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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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More terms from John W. Layman (layman(AT)math.vt.edu), Feb 24 2003
a(18)-a(24) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 03 2009
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