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Search: id:A115880
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| A115880 |
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a(n) is the largest positive x satisfying the diophantine equation x^2=y(y+n). a(n)=0 if there are no solutions. |
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+0
4
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| 0, 0, 2, 0, 6, 4, 12, 3, 20, 12, 30, 8, 42, 24, 56, 15, 72, 40, 90, 24, 110, 60, 132, 35, 156, 84, 182, 48, 210, 112, 240, 63, 272, 144, 306, 80, 342, 180, 380, 99, 420, 220, 462, 120, 506, 264, 552, 143, 600, 312, 650, 168, 702, 364, 756, 195, 812, 420, 870
(list; graph; listen)
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OFFSET
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1,3
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EXAMPLE
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a(15)=56 since the solutions (x,y) to x^2=y(y+15) are (4,1), (10,5), (18, 12), and (56, 49). The largest x is 56, from (x,y)=(56,49).
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CROSSREFS
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Cf. A067721, A115878, A115879, A115881.
Sequence in context: A131595 A124228 A115879 this_sequence A078037 A088508 A142457
Adjacent sequences: A115877 A115878 A115879 this_sequence A115881 A115882 A115883
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KEYWORD
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nonn
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AUTHOR
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Giovanni Resta (g.resta(AT)iit.cnr.it), Feb 02 2006
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