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A230563
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Smallest number that is the sum of three positive n-th powers in at least two ways.
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15
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OFFSET
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1,1
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COMMENTS
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a(7) > 33055^7 ~ 4.31*10^31 (if it exists). Duncan Moore, Oct 07 2017
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REFERENCES
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G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers, section 21.11.
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LINKS
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EXAMPLE
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5 = 1^1 + 1^1 + 3^1 = 1^1 + 2^1 + 2^1.
27 = 1^2 + 1^2 + 5^2 = 3^2 + 3^2 + 3^2.
251 = 1^3 + 5^3 + 5^3 = 2^3 + 3^3 + 6^3.
2673 = 2^4 + 4^4 + 7^4 = 3^4 + 6^4 + 6^4.
1375298099 = 3^5 + 54^5 + 62^5 = 24^5 + 28^5 + 67^5.
160426514 = 3^6 + 19^6 + 22^6 = 10^6 + 15^6 + 23^6.
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CROSSREFS
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KEYWORD
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hard,more,nice,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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