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Search: id:A007527
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| A007527 |
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Numbers that are not the sum of 4 hexagonal numbers.
(Formerly M3793)
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+0
4
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| 5, 10, 11, 20, 25, 26, 38, 39, 54, 65, 70, 114, 130
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The sequence is complete. "In 1830, Legendre (1979) proved that every number larger than 1791 is a sum of four hexagonal numbers". See http://mathworld.wolfram.com/HexagonalNumber.html and reference : A.-M. Legendre, Theorie des nombres, 4th ed., 2 vols. Paris: A. Blanchard, 1979. It is easy to check all numbers <= 1791 by computer. - Olivier Pirson (olivier_pirson_opi(AT)yahoo.fr), Sep 14 2007
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REFERENCES
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R. K. Guy, Every number is expressible as the sum of how many polygonal numbers?, Amer. Math. Monthly 101 (1994), 169-172.
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LINKS
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Eric Weisstein's World of Mathematics, Hexagonal Number
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CROSSREFS
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Sequence in context: A136822 A120513 A004757 this_sequence A033894 A033649 A050680
Adjacent sequences: A007524 A007525 A007526 this_sequence A007528 A007529 A007530
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KEYWORD
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fini,nonn,full
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AUTHOR
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njas
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