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A018890
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Numbers whose smallest expression as a sum of positive cubes requires exactly 7 cubes.
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6
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7, 14, 21, 42, 47, 49, 61, 77, 85, 87, 103, 106, 111, 112, 113, 122, 140, 148, 159, 166, 174, 178, 185, 204, 211, 223, 229, 230, 237, 276, 292, 295, 300, 302, 311, 327, 329, 337, 340, 356, 363, 390, 393, 401, 412, 419, 427, 438, 446, 453, 465, 491, 510, 518, 553, 616
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OFFSET
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1,1
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COMMENTS
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It is conjectured that a(121)=8042 is the last term - Jud McCranie
An unpublished result of Deshouillers-Hennecart-Landreau, combined with Lemma 3 from Bertault, Ramaré, & Zimmermann implies that if there are any terms beyond a(121) = 8042, they are greater than 1.62 * 10^34. - Charles R Greathouse IV, Jan 23 2014
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REFERENCES
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J. Roberts, Lure of the Integers, entry 239.
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LINKS
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MATHEMATICA
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Select[Range[700], (pr = PowersRepresentations[#, 7, 3]; pr != {} && Count[pr, r_/; (Times @@ r) == 0] == 0)&] (* Jean-François Alcover, Jul 26 2011 *)
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CROSSREFS
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KEYWORD
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nonn,fini
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AUTHOR
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Anonymous
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STATUS
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approved
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