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Search: id:A115881
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| A115881 |
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a(n) is the largest positive y satisfying the diophantine equation x^2=y(y+n). a(n)=0 if there are no solutions. |
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4
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| 0, 0, 1, 0, 4, 2, 9, 1, 16, 8, 25, 4, 36, 18, 49, 9, 64, 32, 81, 16, 100, 50, 121, 25, 144, 72, 169, 36, 196, 98, 225, 49, 256, 128, 289, 64, 324, 162, 361, 81, 400, 200, 441, 100, 484, 242, 529, 121, 576, 288, 625, 144, 676, 338, 729, 169, 784, 392, 841, 196
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OFFSET
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1,5
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COMMENT
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The corresponding least y is given by A067721(n).
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EXAMPLE
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a(15)=49, since the solutions (x,y) to x^2=y(y+15) are (4,1), (10,5), (18, 12), and (56, 49). The largest y is 49, from (x,y)=(56,49).
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CROSSREFS
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Cf. A067721, A115878, A115879, A115880.
Sequence in context: A010649 A067721 A021237 this_sequence A077809 A060734 A075594
Adjacent sequences: A115878 A115879 A115880 this_sequence A115882 A115883 A115884
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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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