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A225106
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Prime powers (A025475) that can be represented as a sum of two distinct prime powers.
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2
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OFFSET
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1,1
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COMMENTS
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The next term, if it exists, is bigger than 2^64.
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LINKS
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EXAMPLE
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9 = 8 + 1.
25 = 16 + 9.
81 = 32 + 49.
125 = 121 + 4.
512 = 169 + 343.
5041 = 128 + 4913.
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MATHEMATICA
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nn = 10000; p = Sort[Flatten[Table[Prime[n]^i, {n, PrimePi[Sqrt[nn]]}, {i, 2, Log[Prime[n], nn]}]]]; p = Join[{1}, p]; t = Union[Select[Flatten[Table[p[[i]] + p[[j]], {i, Length[p] - 1}, {j, i + 1, Length[p]}]], # <= nn &]]; Intersection[p, t] (* T. D. Noe, Apr 29 2013 *)
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PROG
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(C) see link.
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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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