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A374230
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a(n) is the smallest number which can be represented as the sum of four distinct n-th powers of primes in exactly n ways, or -1 if no such number exists.
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2
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(2) = 423 = 2^2 + 3^2 + 7^2 + 19^2 = 2^2 + 3^2 + 11^2 + 17^2.
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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STATUS
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approved
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